I had a somewhat similar experience. I took a CS class in high school and, having had something like a four-year head start, did pick the material up somewhat faster than other people.

The biggest difference I noted didn't have anything to do with what the other students did in their spare time. Rather, the major difference was that some students would immediately ask for help as soon as they ran into any sort of trouble where others would spend some time trying to overcome the problem themselves.

The latter approach is far more important than anything you do in the subject itself--it teaches you the skills you need to solve problems yourself. Forcing yourself to sift through documentation, try different approaches and just sit there staring at the screen and thinking prepares you for similar problems in the future where just asking for help only teaches you how to solve your immediate issue (at best).

This post is gender-agnostic because it applied to both boys and girls in my class. I'm sure there are plenty of gender-specific issues as well, but this was the single most important factor I saw in how well other students did.