Winning major trophies like the Champions League or a league title in Career Mode requires sustained excellence. This is a season-long 'boss battle'. You need a strong, deep squad to handle injuries and fixture congestion. Effective squad rotation is crucial to keep players fit and avoid burnout.
Tactical flexibility is also important. Be able to switch formations or playstyles depending on the opponent. Invest in scouting and youth development to ensure a pipeline of talent. Maintain high player morale and keep the board happy. Consistency in both league and cup competitions is the ultimate challenge.