Formations

Alot of us use 4-5-1v against equal or stronger teams and 4-2-3-1 against weak teams achieving pretty good results.
Some also watch out for an AMC, 4-5-1v if against a team with AMC as a DMC is required to counter him.
Frankly i feel all formations work, i have lost to some really weird formations. Just make sure your formation does not have the red exclamation mark

Associations

In the overview screen, there should be a box beside your team? I am not sure, never created an association.