Welcome to live as a military "other half!"
It's far from easy. One big issue though is what you're doing. If you're working, then you could consider, once he's out of training, moving to wherever he'll be posted, renting somewhere and working there. Likewise, if you've been together long enough to consider getting married, you can then apply for a quarter to live it. Those things might be a bit down the line time-wise, but they're worth bearing in mind; it does get better.
Other than that, without wanting to sound harsh, you'll need to be quite independent. If you're in a "clingy" relationship it will be extremely hard. When he's been working himself half to death through basic training, the last thing he wants to do is spend his one free hour in the day listening to his girlfriend in floods of tears. You need to be strong for him, otherwise he'll just resent you in the end. I saw it happen quite a lot to mates through training and students I've worked with; the girlfriend is constantly angry or upset that he can't get a weekend off, or that there's some other draw on his time, or that he can't ring for more than 20 minutes. After a while, he stops ringing the girlfriend as much because frankly, with so little spare time, she's just a hassle. It then doesn't take long for him to get fed up of all the moaning when he does see her, and they go their separate ways.
So, you'll have to be a bit resilient, as you're definitely going to have to face big chunks of time without him in the future, and when he does get ahold of you, you need to be careful not to just complain about how long until you see him! You will need to be independent and you'll need your own life; your own job, education, your own mates, your own hobbies, etc etc. And when you're a bit older, and he's a bit more settled, things are a lot easier unless he's spending 5 months in Afghanistan or something.