+118723 1) Lots and lots of repetetive practice.
2) When you are are using a formula never look at the formula when you are using it.
Look at it, try to imprint it (short term) then write it for you question. Then you can look back to check you got it right. Eventually you will just know it. :)
3) Always write down formulas so that you are constantly imprinting them on your mind.
4) If you are struggling because of an earlier concept that you haven't totally 'got' yet, go back and practice or learn that concept. Maths is one concept on top of another on top of anther etc. Most people (if they study maths long enough) eventually reach a brick wall because there are too many earlier concepts that they really do not understand and eventually they just cannot really go any further. ALWAYS make sure you understand underlying principals.
5) There are heaps of you tube clips to take you over earlier (or current) concepts.
I hope that helps 
(This is not really for a test - it is all the time.)
