The cup draws are decided looking at the AvQ of the best 14 players of all teams.

So, the 64 teams with best AvQ of your server, participe in the best AvQ cup -aka called years ago Shark Cup- then the 65th to the 128th are inside the 2nd cup, and so.

To reduce the quality of your cup you should decrease the AvQ of your team before the season starting. In my case I had 14 contracts to renew this season, many of my best players, thats why I have a "easy" cup.