Seems like many people doesn’t understand this, but actually is very simple (and very true this days on real football…)
No matter what team you choose to start your career, the team chemistry will always be set to 39. You may think that it increases just like the job security and by the end of the season you will have the Team Chemistry bar (those two gear-teeth icon on the Career Central screen) completely full, but the truth is that you will be lucky if you reach 50!
It may take more than you think to fill up that bar. But why? Because a team is not just gathering stars and let them play and win everything.
A team needs that all his players know very well one to each other, and for that they need to play several matches together. So if you are one of those that by the end of the first season have sold almost every player of the starting line-up the team came from, you are on the wrong way.
Every match will give a player (in the starting line-up) some “Team experience” points (you can track that in the Squad screen). At the start all begin with 0, by the end of the season it well could be at 35-40 if they played most of the games.
There’s not a magical formula to have this bar filled up quickly. The only certain and known way to do that is by keeping your team together all the time you can.
Am I saying that you don’t have to bring new players to the team? No, what I’m saying here is that whenever you need reinforcements you are very welcome to do that. But you need to keep your team structure almost untouchable, and players with more experience will make your team keep his chemistry.
Keep in mind too that team morale will affect chemistry. If you are in a lose streak, the chemistry will go low. Winning streaks may rise the team chemistry a little bit.