For the ailerons, more than likely, there is a twist in a wing panel (or both). This is not unusual in open framework wings with monokote type covering. You can often remove the twist by heating the monokote while twisting the wing panel in the opposite direction to the twist. Keep working with it until the ailerons are neutral.

Beyond that, there are some procedures for trimming that go step by step. The NSRCA website has one of them. check the link below.

http://nsrca.us/index.php/all/flying/177-trimchart

Woodie