Like for MANY differentiation questions you can start dy/dx-ing. 

Trigo you can look for clues like sin(20 + x)  < Additional formulae
                                                        sin 2x < Double angle formulae
                                                        sin x + 2 cos x < R-formulae
                                                        cos x + cos 3x < Factor-formulae
Algebra can't really help lah, but usually my steps is,
1) Try to think of the chapter that have the question
2) Use the methods (eg. Chapt 4 -> Polynomials, then f(x) it first)
3) Try at least one step, if still can't solve then tear the paper skip the question.

Remember, seize the 2 hours to chiong all you got.

Have fun
Melvin

Class 406'09
Jaywalkers
A class who played and worked hard
6:12 PM