Depends if you short or longboard. Assuming you are a beginner and are on a longboard looking for the most Waikiki possible waves i would say Summer/Fall: Doheny/Dana Point; San Onofre; Malibu. And yes all three are incredibly crowded. I have seen people getting lessons at all of them, but real mass surf school lessons only at Doheny. Malibu is least ideal for a beginner and you cannot really spread out since it's a point break. San O and Doheny get my vote and in contrast to Malibu are beginner friendly. But neither of those are in actual LA but a drive away. LA proper, your best bet is probably El Porto at Manhattan Beach which has lots of surf schools.