1. I know messaging almost everyday is a must. But what about calling? Will calling frequently help improve our relationship as well?
Yes, calling helps a lot, and a lot easier now with the internet. Skype/facetime etc. Spending an hour or 2 talking over the weekend is kind of like a date
2. What do you (BF or GF) talk about on a daily basis?
The past, the present, and the future. It is fun to reminiscent about what already happened together. It is great to update them about what is currently happening (friends, work, family, movies, news etc). And it is a good thing if you can plan a future together.
3. How often would you travel to meet up, given the distance isn't too Far?
Hard to say, very dependent on the situation. My sister has been in Auckland for the past 10+ years, and brother in law goes over every 18 months or so for 2 months.