Set your Youth Team level to 5. The next year in Master League you
should have at least two stars in your youth team. For example, the
youth team spotted Klasnic 16 and Amanatidis 18 when using Barcelona.
Other teams have different stars. Go to advanced search, and put 15 to
19 for the age. For example, Carson in Sampdoria and H.Larsson in Racing
Club. Teach them a lot of Ability Cards and Positions and loan  them
out to make them better.