My husband and I are old pros at the whole long distance thing
We dated long distance for four years, most of that 1000 miles apart, with a brief stint of him across an ocean. We made it a point to talk every day. I used to send him cards and stuff, which he always liked, but never really got into sending them back to me (though, apparently, the fact that he mailed me something twice within a school year led the postal guy at his school to ask if he was in a long distance relationship, so that might tell you something...). We also used to use video chat, but we'd mostly be busy doing other things, generally homework or something. It was just nice being able to look up and wave and feel like we were in the same room.
We're currently in a commuter marriage. He works out of state 50% of the time. We make the most of our time together, going for runs together, cooking together, and a lot of time just cuddling. We still try to make it a point to talk to each other every day. Texting throughout the day helps too, telling him about little things going on. He generally doesn't have time to respond, but I feel like it keeps us closer and he's still a part of my everyday life.
One of the best things you can do, though, is enjoy your alone time. I know it sounds crazy. But if you have hobbies or activities and friends that make you happy and keep you busy, you're not spending all your time missing him plus you'll have a lot more interesting conversations telling him about what you did with your day.
I know it's tough. It's still hard on us and we've been at this for quite some time. People probably think we don't actually like each other

We do, I promise! It's a lot of work, but the best things to keep a long distance relationship strong are the same as a close proximity one: Communication, honesty, and trust. Honestly, I think my husband and I have one of, if not the strongest relationship of anyone I know simply because we've really gotten to hone our communicating skills.
Good luck! It'll be worth it in the end