One of the things that I've always enjoyed about robotics is that it is a 'systems' discipline. It employs mechanical, electrical, and software components into a complete system. My experience after 25 years of robotics club meetings is that there are few people who can 'do it all' and that means you pretty much have to team up with people who have complementary skill sets.

So depending on where you find yourself most comfortable consider focusing on that part of the problem. Could be algorithms (software focus), could be mechanics, could be 'mechatronics' (which is the term the local community college uses for a combined electronics/mechanical engineering sort of curriculum).