SAT and ACT
You mentioned only the ACT. I would definitely recommend taking the SAT in addition to the ACT. The two tests have different approaches and often times a student who doesn't do well on one may do well on the other. Have you looked at prep courses? Some can get very expensive but there are cheaper alternatives (online courses, study books, etc.). Other threads have discussed that......I'm sure with a quick search of the forum you'll find some advice. Lastly, if possible take both tests multiple times. Good luck!!