There are many threads on GC where members have developed guides/strategies on something (including many comprehensive write ups)
I will post some that I have. If you find something noteworthy (in GC), post a response and I will update the post accordingly.
Math:guide to series and sequences... arithmetic and geometric
. benjibooMath: Absolute value (Modulus).
WalkerCombinations, Permutations, and Probability - References.
WalkerSlingfox's GMAT Strategies (Condensed).
SlingfoxQuant notes for PS and DS.
Verbal/AWA:AWA Guide: How to get a 6.0
. chineseburnedGMAT Idioms
crejocSpidey's Sentence Correction Notes
Spidey's notes from Test Magic ForumThe Idioms Test.
sarubaSlingfox's GMAT Strategies (Condensed).
SlingfoxCR for beginners.
Other:Walker's guide to Slide Presentation.
WalkerCompiled Interview Questions.
peaceyallRhyme's Totally Fallible Guide to Interviewing.
RhymeGMAT CAT Timer.
More to come as I dig up other threads.
[highlight]Please follow this Format:[/highlight]
Strategy Discussion Thread | Strategy Master | GMAT Debrief| Please discuss strategies in discussion thread. Master thread will be updated accordingly. | GC Member Write Ups
GMAT Club Premium Membership - big benefits and savings