I thought the practice tests were WAY easier than the real OAT. (especially the one the OAT board sends to you when you register.. i scored a 380 when I took that one and that was no where near my actual OAT score) So, take the practice tests with a grain of salt. I studied every weekend for a few months and then every day for awhile the six weeks before the test. Good luck!
I took tho oat 4 years ago, although I became a dental student. I only studied for organic because I had not had it for 2 years and a little bit of optics because I had heard it might be on.
I think I got a 380 in organic, 360 in physcics, and around 350 in the other sections. I remember not finishing the quantitative reasoning and having to guess on 7 in a row ( I think I put all the same letter so I would get at least some right)