well it's simple you just need to train them in the training section and i suggest u choose the very hard level drills and make sure u have enough rests
because if u want ur player to get his SA as soon as possible u need to use the rests and train him again and again
well that's what I'm doing right now i've been training my striker 35 for around 4-5 days and he has 35 sa points(i could even get more if i was more active)