Quick tips: Should get you an A-A*
1) Hard work (most obvious)
2) Motivation
3) Healthy eating (Allows your brain to hold information for longer)
4) Exercise (This links in with 2, it helps with motivation and also links in with 3)
5) Study timetable (Create a flexible timetables, relaxing times, study times, not just for chemistry but for all subjects)
6) Early bed time (You're brain will be fresh to absorb more information the next day)
7) Little distractions (Especially You're phone, going on inappropriate sites like mini clip or stuff like that)
8) For chemistry its important to do as much calculations as you can, example, Moles, Bond enthalpy etc...
9) Go through as MUCH reactions as you can. This will make you get a SOLID A. For example when mixing two specific reactants what can you observe.
10) Go through AS MUCH PAST PAPERS as possible!
11) DON'T JUST DO PAST PAPERS, DO QUESTIONS ON THE INTERNET!
12) Have frequent breaks, ideally after every 90 minutes of studying for 15 minutes.
13) And finally have some almonds
! - Or other brain food.
Extra: Don't smoke, Drink, Have sex (Unless your married), Watch Porn, Fornicate and all these stuff. These cause a EXTENSIVE disadvantage to learning and studies. Thousands if not millions are at a disadvantage due to this.
As long as you keep your brain happy, you will be happy too.
-Mr Firefreak at your service!