Well im only in season 3, joined the league in season 1 nr the end but got promoted.
Season 2 started slowly but won the last 22 games in a row to be champion, never use the same tactic but normally 4-4-2, change it due to injuries etc.
Season 3 now and won first 5 league games, 3 in a row in Champs League and in play-offs of cup without defeat even against stronger teams..
I dont buy tokens etc, just be careful and dont get into bidding wars although once or twice lost 3-4 tokens. Got a young player end of season 2 through the system and paid the 21 tokens, just saved them up, hes banging in the goals and most expensive squad player.

I always try to have my players at 100% condition without using rests, just rotate the squad when playing weaker teams is a good idea imo. Boosters have to be used on occasion but i rarely have them at maximum morale, mostly superb and even very good is enough sometimes.
Enjoy guys, by the way my team is named Celtic FC !!