While you're getting into magic, learn all you can. Learn heaps of routines, sleights, genres of magic, the lot. Experiment with it all.
Once you've got some experience performing, varying and learning magic, you can begin to pick and choose what will be your core routines. I wouldn't say more than ten for each genre (10 close-up, 10 parlour etc.) but this number varies depending on what your needs are. Maybe you want to work in a restaurant? Is that restaurant pretty small? If so, you might need several routines throughout the night. 3 effects - 3 routines gives you nine routines, and a couple of spares for the odd opportunity.
But really, while you're making you're way into magic, learn AS MUCH AS YOU CAN.
Me, personally I use around 12 close-up effects. 3 routines of 3 with some spares for spur of the moment situations. I also have several impromptu effects, as well as the "specials", the ones I bring out only when I really want to impress.
Ty