GMAT studies (1)

Following the scare given to me by the prep software the other day, I set about putting together a study plan to cover off all the basics. 

Adding to my general need for revision across all the areas in an effort to get my practice times down to under two minutes per question, it is also clear to me that further work on number properties (especially when applied to data sufficiency problems), exponents and general grammar rules would be highly beneficial.

Fortunately the local library appears to be well stocked when it comes to GMAT prep books - and I've spent a successful, if not particularly exciting, day crunching through old copies of 'Kaplan 800' (containing a set of the tougher questions from both verbal and quant sections), McGraw-Hill's 'Conquering GMAT Verbal' (fairly simple) and 'Kaplan's GMAT Verbal Workbook' (which in parts repeats some of the Kaplan 800 questions, but is otherwise quite good). 

Hopefully, with a couple more practice question sets in the coming days, I will break some of my remaining bad grammar habits in time for the proper GMAT (when it comes to assessing test answers anyway).

Free materials
http://www.beatthegmat.com/
I stumbled across this site last night, and it seems to contain a number of subject specific forums stuffed with practice questions posted by members of the online community.  (some of these questions may have been  'borrowed' from a collection of the more popular textbooks....)

As a source of further practice material I'm sure I'll take a look at the site again in the future - though have noticed that for some questions posted, whilst a large number of community members are more than happy to post explanations of why the answer they chose is the right one .... it's possible that they (and a large number of others posting to the thread) are quite wrong!  Look out for posts tagged 'OA' as they (in theory) should contain, or link to, the 'official answer'.

One further useful note; it appears that the GMATprep test answers do not provide explanations - there are a number of beatthegmat forums that attempt to help you out in this respect.