What can I talk about with my girlfriend?

learn more about her interests and hobbies. crack jokes make her laugh. or even talk about yourself like your interests. spend more time with her and get to know her better by taking her out or hanging out with her. then you'll know what to talk about.

Everything and anything.

Tell her about a cool happening that you heard of, randomly or on topic.

Talk about something interesting that happened to you lately.

Ask her how she is doing, if she is excited about something, etc.

Ask how her weekend was.

Play the random game, as a conversational tool. Both of you take turns asking a question about the other. Conversation will spawn out of the answers, most likely. Make sure she knows you are playing the game though. Ask, it can't hurt.

Ask her if she has seen anything good on tv lately, or ask if she caught a specific thing on tv the other night.

Start a "Did you ever think about/wonder" discussion. Like Did you ever think about where the world will be in the future. Did you ever wonder how this or that happens. In could be in context of your environment- use what's around you to your advantage. This is why phone conversation can be awkward- you can't see what the other person sees.

interest and hobbies, things about her
and then link things about you if it is common between the both of you