I really want to increase my ACT score by at least 2 points, advice?

I took the ACT test two times and scored a 28 composite on both of them. I've taken lots of practice tests and that's where my issue is. I sat in class during a "relaxed" day and I timed myself for each test. I did this numerous times and I scored in the 30s for all of the subscores...and that's with people around me being loud and talking. I don't know if it's a psychological factor when I take the real test, but I really want to increase my score and get at least a 30. Is anyone else like this? Any tips? Thank you very much in advance!