What do you do?
Pray that you will be luckier than me haha
Nah, seriuosly, i've never had a girlfriend, ut if i can give you an advice would be something like this:
1. sms her first once in a while, either you could use whatsapp or something. Try to relax and hava a playfull chat with her, but always listen to her, and if you "may ask to her" ask details if she either tells you a story or something: Everybody loves talking about themselves (I'm telling this in a good way tought

). Remember, be reasonable, playfull and A LITTLE bit flirtu (not obvious, but show a little of interest so she would guess some interst of your part), remember, a little interest is good, too much, not. Don't be afraid to tell some innocent jokes or something, but try to be yourself, relax.
2. Don't message her daily, remember that both of you have a life (or at least i guess haha, just kidding), and if you don't get one. What i mean? Even thought you wnat to know her, she can't be your world buddy, what would you do if she's not around? You would obviously miss her, but she can't be all your happiness because of the same reason i just gave to you. Remember, you ARE happy, and if you two become friends or even something else, you would be happIER.
3. She has friends, familly and a lot of people (or i supose that), so try to be sensitive on how you talk to her or how you say everything: It's not the same thing asking "What are you doing?" or "Where are you" than "How are you?" or "How was your day?"
4. Coming back to your simple quiestion, everyonce in a while is fine, you don't need to wait 2 weeks to contact her, because she might suspect some interest of your part, and if you don't contact her, she might doubt. Chat with her whenever you want as long as it isn't 24/7 and you aren't interrupting or something (Remember that you both have a life). Concerning the calls, i would suggest you to start calling her once you two gained a little bit more confidence/trust with each other.
Good luck

, we're here for everyone.
If i misspell or something, sorry.
It's ok to wait other suggestions tough. As i said, never had a girlfriend before.