So, my bf and I were long distance (Sweden-Canada) for about 5 years before he moved here. I'll start by saying we had it easy because we started out long distance, and I honestly don't know if I would've been able to deal with switching from same city to LDR. Still, a few tips (in to particular order): get really good at talking. Talk regularly, about all kinds of stuff. Make time to talk, and honor the "appointments" you've made with each other. Skype dates, like real dates, sometimes get cancelled because things come up, but don't get into the habit of thinking because it's online it's automatically second place to other things. Do things "together" apart. Maybe play a game together, do a project, learn a language, watch a TV show. My bf and I watched GoT, Doctor Who, a few other things together like that, we'd say "let's watch episode X today" and the next time we talked we'd discuss it. Plan visits well ahead of time to have something to look forward to. Do fun stuff on visits, but not only "vacation/special occasion" stuff. Share your everyday lives with each other when visiting, hang out with friends, lounge around the house (and go out and do the special stuff too). If shipping allows it, send each other care packages sometimes. I assume neither one of you wants to be in a LDR permanently, so make some kind of plan. Ok, you don't know how long he'll be there, but chances are after a few months you'll have some sorta feel for whether he wants to stay long term or not, and then you can sit down and talk about how long you each feel the LDR thing can work for and what your options are for the future.

Good luck to you, I imagine it'll be a hard adjustment. While I was quite happy in my LDR, I never had to adjust from being together all the time to being far apart, so I can't give much advice on that I'm afraid.