It's hard enough to make local relationships work, but having miles, States, and sometimes even an ocean between you makes it even more difficult. However, successful long distance relationships can and do exist. Here's how to give yours every chance to survive and thrive.

[edit] Steps

Ask the important questions at the onset, to make sure you are both clear on the parameters of the relationship. Setting parameters such as naming your relationship ( dating, seeing each other, boyfriend/girlfriend, engaged)as well defining exclusive(limited to one person,) non exclusive. These can be difficult and awkward questions to ask, but will save you great heartache and misunderstanding down the line. Example: "Are you open to the possibility of relocating if the relationship should become more serious?"or "What are you looking to get out of the relationship?". Stating your end goal or ideas will allow each person to maitain what they need.
Communicate in some way every day, more than once if possible. Since you won't be seeing each other, it's important to establish and maintain an emotional connection. These don't have to be long, in-depth conversations (though those should occur sometimes). Tell each other about your little triumphs and tragedies. Ask for advice. Use an instant messenger program or VoIP for real-time chat, or web cams for that visual connection, but while instant messaging and e-mails play a large role in long distance relationships, remember that they can in no way replace verbal communication. E-mail is great so make sure you use it, especially if long-distance phone calls put a strain on your budget.(Even though phone calls might get a little too expensive, there are special cards if you are to call each other from different countries, there will be no problems with costs since it is very cheap. We highly recommend you get one of those cards, it will be a lot cheaper and from experience E-mail and instant messages makes it easier to misunderstand each other.) Write love letters. Send small gifts or flowers for no reason. In this case, quantity is as important as quality. You may discover an advantage over others whose partner is close at hand - you don't take communication for granted!
Do things together. Defy the distance. Frequent communication is a great thing when it can be managed in a long distance relationship. However, constant communication over the phone alone may tend to drag people down in the long run. It's important to do other things together besides the usual phone call. Just think... people in short-distance relationships do not spend the majority of their time talking, but rather doing things with each other. Try to replicate this by finding things to do together such as watching a TV show or movie simultaneously. For an extensive list of more things you can do with each other (or for each other) click here: [1]
Take advantage of the benefits a long distance relationship offers: more time with friends and/or family, no arguments over toothpaste caps, the pleasure of seeing your sweetheart again after a long absence, time to mull your options (rather than snapping at your partner impulsively) before you respond to that email s/he wrote that seemed so rude the first time you read it, etc. Most important, being far apart gives you a chance to maintain your individuality - something that can get lost in the shuffle when couples spend all their free time together.
Pursue common interests, even if it means pursuing them apart. If there's a movie you're both interested in seeing, watch it individually and then call each other afterward and talk about it. Read a certain book at the same time. Stargaze while on you're on the phone. Set your watches to go off at the same time every day, and synchronize your alarm with that of your partner. Make it a point to think of each other when your watch goes off, and revel in the fact that he or she is thinking about you, too. Find creative ways to bond.
Avoid the temptation to be controlling. People have free will and no one can or should control another person. As long as you are both interested in being in the relationship, you will stick with it and distance will not make a difference. As soon as one of you decides the other is not a good match - or someone else is a better match - your relationship ends, whether you live 3000 miles apart, two streets over, or share the same bed with your wedding picture on the wall. You are going to have to trust each other completely if this relationship is going to work.
Talk about your future together. Assuming that ultimately you'd want to live together, discussing how you're going to get to that point will help you prove to each other that the relationship is going somewhere and that your efforts and frustrations are not in vain.
Know when to say good-bye. While this is tough in any relationship, this can be especially hard over long distances. When communication becomes one-sided or sparse for too long and for no apparent reason, when arguments (yes, you'll have them) become too frequent, when the whole thing just seems like more trouble than it's worth, it's time to re-evaluate the relationship. Either you'll decide to go your separate ways, or you'll get closer for having overcome another obstacle to your happiness together.
Remember things will get better with time, and even the relationship will become better. Have hope.

[edit] Tips

A long distance relationship is no different from a proximal relationship in that they both require a great deal of work, excellent communication, patience, sacrifice and understanding. But you will have to work extra hard to maintain the communication and to stay focused enough to not let your daily life interfere with your desire to be with the other person. Don't forget them or you can forget the relationship and it will all be over.
Sometimes phone/email/IM communication can get bland... don't forget there are other ways to interact! Utilize the internet and find things you both can do together. It takes the pressure off constant talking, and can be fun. Click here for a list of things for LDR couples to do:[2]
One of the hardest parts of a long distance relationship is connecting when one person gets busier than the other. If this happens in a relationship it is important to maintain communication. If you are the busy person, try to warn your partner ahead of time that you will be working many hours and may have limited time. If you are the not-as-busy person, take advantage of the time by picking up a new hobby, getting in shape, reading a new book, etc. Flexibility is very important.
It helps to have a solid time in the future for when the long distance part of the relationship will end, no matter the time length. Without it, the relationship can begin to mold into something that is always distant - even with great communication. With it, each person can see the point at which the distance will end and work harder to keep emotions readily available.
When talking to your partner, take note of things they enjoy the most (hobbies, day-to-day activities, etc.), and do a little research on it so you have more to do when you see them next. For example: If your partner likes to dance, find the location of different clubs where you will see them next. If you don't know how to dance, take lessons and you will impress them by your willingness to make an effort on their behalf.
Buy a game that you can play together over the internet, such as a MMORPG (massively multi-player online role playing game). You will be able to chat while playing and it will give a greater feeling of togetherness.
Mail each other scented clothes.(Or even clothes smelling of your sweat - pheromones are a great way to establish intimate contact.)
Send each other spontaneous ecards.
Make a creative countdown and mail it to your partner to enjoy until you see each other next. For example, create a photo calendar, with something you add for each day to describe what you love about them.
Do not set unreasonable expectations for your visit and/or future plans. Fantasizing about the visit is fine, but not out loud veribally or by email to your partner. Instead, enjoy the excitement of the surprises to come. By stating that a surprise is coming can allow to much thought time for the reciever and leaves both of you open to disappointments.
The Long Distance Relationship Guidebook is a well-balanced, practical book for couples in long distance relationships who need some guidance.
Buy a webcam so you can chat face to face and see each other, so when you meet you will remember what they look like.
Consider the fact that living far apart gives you both a chance to grow as individuals. Some couples break up to "find themselves", but in a long distance relationship you both have enough space to do your own things and still have a connection.

[edit] Warnings

Remember, every kind of relationship takes hard work and dedication to your loved one or partner, whether it's long distance or proximal. If you and your partner are willing to take these steps, then expect bumps and turns in the road. These bumps and turns will only help contribute towards a relationship.
Long distance relationships are not for the faint of heart. They can be very trying - but so can proximal relationships.
Long distance relationships can and will test you and your partner; you need to trust him/her entirely as paranoia can play a major part in the demise of your relationship. Also, these kinds of relationships can bring a lot of disappointment and heartache--depending on the time you spend away from each other it is VERY important that if you want this relationship to work you must make a great effort not to drift apart.
Long distance relationships are difficult, as you are emotionally attached to a person you cannot touch or comfort (hug, kiss, hold hands), and this can hurt your heart and wreak havoc with your emotions. The only way to make these relationships work is if you and your partner honestly believe you will be able to survive without each other for a considerable amount of time without the need or desire to be with someone else.

[edit] Related wikiHows

[edit] Sources and Citations

10 Rules To Make Long Distance Relationships Work Article about the pitfalls of long distance relationships and how to overcome them.
Guide to Having a Great Long Distance Relationship A Quick Guide about Developing a Healthy, Happy Long Distance Relationship