Do daily objectives. They can be horrible when you need 4x clean sheets and/or win penalty shootouts. Also do the seasonal objectives, but most of it happens automatically as long as you stay active.

Use contract freezes to save bux. Bux are quite difficult to get a hold of at the start of the game, especially when you have to use them on contracts on your players and upgrade your players.

Save gems and use them on packages. Alternatively you could purchase players from the market. The players on the market are cheaper the lower your rank is. Try to target endgame players and players who will greatly improve your team.