Tutorials
Costume Care: Tips on how to keep your costume neat and clean
Cosplaying Tips for the Convention: Tips on how to present and maintain your costume at the con
Cosplay.com Tutorial Checklist: A great list of tutorials from props to hakama to resin casting and more
The Costumer's Manifesto: Simply the best resource out there for all costumers - Very highly recommended!!
Armor
Alley Cat Scratch Armor Cheats
Amethyst Angel's Armor-making 101
Armour Archive: Patterns for real armor
BioWeapons.com: Guyver Bio-Armor Construction
Cosplay.com Forums - Insulation Foam: Very useful for making armor and weapons
PaperWings' Bondo Armor Tutorial
PaperWings' Fiberglass Armor Tutorial
Wonderflex
Boot covers
Sarcasm-hime's Boot Cover Tutorial
Cosplay.com Boot/Shoe Cover Thread
Love Meeko's Boot Cover Tutorial
Gloves
How to Make Gloves
How to Make a Pair of Gloves
Vintage Sewing - How to Make Gloves
Somewhat Stretchy - Catsuit
Wigs
Cosplay.com Forums - How to Make A Ponytail
Cosplay.com Forums - The FW Ink Wig Dyeing Method
Cosplay.com Forums - The Sharpie Wig Dyeing Method
Amphigory - How to Curl a Wig
God Save The Queen - How to Curl a Wig
Katie Bair's No-Sew Wefts
Kukkii-san's Weft Sewing Tutorial: I could write my own tutorial for this since I do it pretty regularly now, but Kukkii-san was the person I learned this method from, so I'd like to give her full credit. Her tutorial spans over several photos in her Cosplay.com gallery.