When it comes to coursework there are two tracks:  IGETC (or the second general ed path called breadth) and course fulfillment for the major.  Of the two, the most crucial to get completed are the major courses. Ideally, have most done by the fall when you apply.  Pile up the gen ed or IGETC at the end because while you need to complete a certain number of them, depending on path, the UCs aren't interested in gen ed beyond your getting them done.  That said, obviously they will look at overall GPA and you need at least the first English course and quantitative math done by the fall.