i am sure there could be a lot more tips to add for the cleaning of a closet...but...i say...since for some this task can be quite overwhelming...the simpler the better...
consider shelf life: if you never wear it...apply the twelve-month rule...and recycle (or consign)...if you must...allow yourself a few exceptions...
discern: be ruthless...or bring in a ruthless friend...preferably one whose style you admire...
document: borrow a camera and document outfits you come up with...
fill gaps: list what you need...and buy accordingly...
organize: redesign your closet so you can see everything...and group things...whether by size...color...or use...in a way that makes sense to you...
restore order: make your closet a haven of order and function...there can be method to the madness....you just have to impose it...try on outfits in front of a full-length mirror...weed out what no longer fits...determine what you reach for daily and give it prime real estate...
recycle: keep a box on the floor for thrift-shop donations...
party: when the purge is finished...invite friends over for a give-away...it may help to know that someone you like is wearing a beloved item...
and if this truly is something that is overwhelming...and you find yourself avoiding it at all costs...it may be well worth the money spent to bring in a consultant to help you make sense of your closet again...i can assure you going forward...you will be happy your closet is in order...