Also do not forget Affiliated clubs are very important! I'm Liverpool and I've had two Worldies from Brondby on my save, that came through in my intake. Also for staff, make sure you have some youth coaches with excellent mental/hidden stats, as these affect the youth players personality, and not just focus on a five star training rating. It will normally say on your youth players favored personnel which staff members have influenced him.
Also appoint a great Head of Youth development, and have him handle your intake in staff responsibilities. A stat i think is often overlooked, is to appoint a HoY that prefers the same or a similar formation to your own. This means you'll bring players through in a variety of positions, and in ones you want. E.g. if you play 4-4-2, and your HoY prefers a formation with an AM, could get annoying if you keep getting AM's.