I have one of the strongest teams in my league and usually win something most seasons. Done purely through the correct training drills to certain players irrespective of their SA. I tend to concentrate on power training my AML, AMR and AMC as they're my most prolific goalscorers. I usually replace everyone else each season or maybe keep them 2 seasons (especially defenders) as I don't think they contribute much and GK skills do not exist in my opinion so not worth giving them much attention either. Each to their own really. What I do works for me. Good luck.