u need to check all of your 19 and under players (age wise)
look for talent 4+
with green consistancy stat 16+
high physical skills
high intelligence - (though low intel is ok for some pos)
ignore what pos it says they play , look at what skills they have
find the eval thread and post your best couple of talents there and see what people say there worth.
as for tips on the rest of it theres plenty on the forums.
but the important ones seem to be
improve your stadium first - focus on vip seats - build on the side you dont already have seats as the area gets closed while under construction.
early on in your team especially against bots use running plays more , once your team improves then shift the focus to passing plays.
when setting tactics make sure your tactic is legal , n that a player isnt playing multiple positions