I've found that revising algebra and index laws really help - with particular emphasis on simplifying them. You reach a certain point where you just immediately see the simplification and can do it right away. Also, always try to keep your expansions as simple and organised as possible (e.g. keeping all the 2^K + xyz... next to each other and the 3^4k + xyz... together, that way you'll be able to see the simplification faster).
Just remember there are 4 steps that you MUST follow:
1. prove true for n = 1
2. assume true for n = k
3. prove true for n = k +1 (or +2 if it's for even integers)
4. statement/reason
I follow those steps every time and I get all marks that the question warrants