I recommend that you learn everything you can about Procedural Law. Unfortunately, many cases are not won or lost on the merits, but because of which side had the better attorney. Law is like a giant chess (or poker) game, being played out between two lawyers, It is the client who stands to win, or lose. You have to know everything there is about what types of motions to file, and when, and the consequences of filing, or not filing, these motions. It sounds very dull, but it is in fact, very important.
Beyond that, explore a little. There are areas of specialization that may not have crossed your mind. Do what is of interest to you!