The more questions you practice the better – you can never practice enough. Make sure that you also attempt the more recent questions (that you can download on the ACCA website). I assume that you have completed studying all of the topics, but do work through all the technical articles on the ACCA website and it is essential that you practice using the word processor and spreadsheet that are used in the exam (especially being familiar with the various functions that are available for calculating NPV, IRR etc..)