Well I think the most important thing in a long distance relationship is to understand what kind of communication you both find satisfactory and feel happy and content with so you guys should I try to find a balance between the time apart and time together.
Communication though is very important and you guys should both make a combined effort to talk things out whenever you feel any things wrong and just trust each other.
I would video call my boyfriend whenever we both felt like it, it may be a bit shaky but since you guys have been dating for long enough there shouldn’t be a huge deal.
I would also send him a lot of pictures of literally anything I found he would like, and he would love it to see them, he’d do the same too. We also used to have a few dinner dates , so we would just video call each other and have dinner together and just talk about our day. Every night we’d call each other to wish goodnight or even fall asleep while talking.
And also like a few others here told you before, you REALLY should tell your partner everything and let him know regularly/often that he’s on your mind and that you’re doing fine as well.
It may be difficult you guys aren’t gonna see each other for a long time; I haven’t seen my boyfriend for almost a year now but when you find a balance between your life with and without them, it’s gonna be perfect for you two as long as it’s a two way thing, not just one of you trying.
All the luck to you two and I hope you have a healthy relationship ☺️