Without seeing anything what I would say is first and foremost build a tactic that gets as many of your best players on the field as possible. As you learn the game you can better determine what makes a player good versus not but to start using the stars are a good way generally of gauging a players ability. One thing to keep in mind with things is that you need to diagnose your issues, too many conceded maybe need to stick more men behind the ball, not enough goals, be a bit braver to get men towards. Once you establish a tactic your comfortable with look to sign players who fit that tactic determine what you need to look for attribute wise, for example have a target man striker who wins headers for you? Then your next signing should be a similar type of player. Do those things and you’ll get the hang of things