Three more games left until the end of the season, but I've already guaranteed my number one spot in the league. Not bad for a noob. Even if I lose all the remaining games, I will win.

So I am planning to plan ahead and prepare for the upcoming season. What are things I should know about? For instance, will there be free agents?

And do you guys advise me buying/selling players now before the season ends? Or is it a better idea to wait for the new season to begin?
I mean, will I be matched with stronger opponents next season if I buy stronger players this season? And is hard-training my players now a bad idea?