Madden NFL 25

A good start to getting this achievement is to stick with whatever chemistry you chose at the beginning of ultimate team because the player you get is worth +10 already to that chemistry. (For example, I took the Redskins with long pass chemistry and got a +10 RG3).

Another good thing to do is if you can buy a gold coach with your chemistry, do it. A gold coach gives another +10, Then, if you play the solo challenge for the first half of the season with that coach's team, you can trade in the gold coach and the helmet for an elite version of that coach that gives +20 chemistry. You would find that under solo challenges - regular season - team name (ex. Washington Redskins, not the road to the playoffs games)

I used those 2 things and filled out the rest of my roster with bronzes, silvers, and one gold to get to 70. If you get an elite coach with 20+ and have the starting player with +10, it shouldn't be too hard to search the auction house for your desired chemistry and find good buys. Buy out items when you can just to make sure no one outbids you.

Hope this helps!