1. Learn the basics and then learn expand and mnaipulate them.
2. Do the question out of a text book and generally the harder ones towards the end will more likely be the exam ones, then compare them to past papers.
3. Learn other methods for doing the same question, if possible, because it will reinforce what you've learnt so you don't keep doing them 'easy way' (also you may find the other way much better-when you've learnt it properly)
4. Read the question carefully.
5. Silly mistakes omgosh yearly, panick, really hard, polynomials, 4/1 =1, 2/1 =1 *woops* try and think clearly if you can. I hope I never make that one again.
Wow I should really start taking my own advice.