I'm currently in a long distance relationship. I'm in Spain and my boyfriend is back home in Britain. We've now been seeing one another for two years(we met at University, he's now graduated and I'm on my year abroad) but we always had a bit of distance issue from the outset. This is because for me home was Plymouth and for him home was Leicester.
He's coming out to see me in three weeks, and I think if at all possible that is the first crucial tip. You must see each other at some point. Although we haven't technically seen each other in three months now we have been in constant contact with letters, emails and telephone calls. I know when I go back at Christmas I've arranged to spend some time with him.. and hopefully if we're still together come June time when I finish here, I'll need to spend some time with him to resettle myself back into the British lifestyle! (It is so different out here, honestly.)
I think the other tip is to not confine yourself if you are in a long distance relationship. If you do meet someone else, who takes your breath away you should not just deny that just because you're in a relationship. I've not met anyone else who has the same effect on me that my boyfriend has yet, but I think whilst you're still young and have the freedom you shouldn't force confinement on yourself. You can definitely look, but in my case I don't want or haven't found something to touch other than my boyfriend.
Also, I think the fact that in long distance relationships the fact that you are comfortable without your other half stands you in good stead because it means you can be your own person, and be with another person at the same time.