[rustyblueyez]

I have to agree with pete_m, that's the way I prepared for it.
If you need learning material for the areas you are not so hot on, get AS/A Level revision texts, they're easier to get into than more comprehensive textbooks and cost/weigh considerably less!
We had a very high proportion of organic chemistry on last years paper, Organic Chemistry for Dummies was great for me.

Don't neglect your written skills particularly practicing essay writing, 1 hour for 2 essays is hard work.

Everything in the GAMSAT comes down to time, there's never enough of it, so learn to skim through the paper and find the questions you can do most easily and go from there.

Good luck and happy revision!