Good luck, you'll be fine
Assuming that you're doing Production of Materials and Acidic Environment:
1) Make sure that you're all good with calculations (Especially with titration, try to avoid silly mistakes like adding the first titration to the titration volume average)
2) Make sure that you've mastered all the equations necessary, such as with the effects of acid rain in which you could mention the damage it does to limestone structures, and back it up with an equation in which an insoluble calcium sulphate precipitate is formed (assuming that it's sulphuric acid)
3) Make sure you know you're practicals really well, such as the molar heat of combustion practical, in which they could ask how you could improve the accuracy of your results, etc. and be able to explain why certain things happened in your experiment; such as why is the experimental value different to that of the accepted value of the molar heat of combustion of 1 - Propanol? Then you say that it may be due to incomplete combustion as indicated by the yellow flame given off by the spirit burner and the formation of soot at the bottom of the beaker/aluminium can (since carbon is a product of incomplete combustion. Also know why certain things are used, such as the specific alkanol mentioned above in which you could say that it is a short-chain alkanol, meaning that it is more likely to undergo complete combustion, etc.
Sorry for blabbering on, but these are the main things you should be able to do before the exam
On another note I've finished my half-yearlies!
