Try some good loans and free transfers in, have your scouts assess the more expensive players available for transfer and try and get players with 3 and 1/2 star ability or above.
Search contract expired players when the transfer window opens, or if it's before then try and sign players on a pre-contract a month or so before theirs runs out.
I'd recommend getting a good poacher style striker if you haven't got one already, pace, composure, finishing, off the ball and dribbling are the attributes you should look for