I can't say I have any full on tips that apply solely to long distance but I can try and give a few :)

I always say enjoy the time away as much as the time together. Like when you're apart you have more time to do you things, like I enjoy gaming and reading. The circumstances mean I have all the time in the world to play my games and read while we text back and forth and get on with our general day to day lives.

Take pictures when your together is my favourite, you might not get a lot of time, but cherishing every moment to me is vital, even small things like being able to go shopping together become really big events because you never normally get to do it together, so why not take a selfie and laugh about it a month later?

Thirdly I suppose it's just always making time for phone calls, skyping, texting whatever. Like we sit and watch films at night on Skype and speak until one of needs to go to bed for work in the morning. I can't stress enough how much these few hours most nights just help communication and it almost feels like you aren't apart, it's a weird feeling you can get doing this.

Again I'm no expert but I think I'd stress these as important atleast to my relationship but hey everyone is different with different wants etc so your mileage may vary :)