* Why can't I find a pattern like the character I'm cosplaying?
Commercial patterns are made for...commercial/mainstream looks. Rather than looking for something exactly like your character's clothing, look for basic pattern shapes that you can modify.
* I don't have a sewing machine. Are gluing & hand sewing feasible options for me?
It all really depends on your patience level and quality expectations. Glue isn't really designed to piece fabric panels together in the same way as a sewing machine (latex being the exception). It can certainly be done, but you simply will not get a fantastic quality costume. Hand sewing is feasible if you have the patience, but do realize that your stitches will not be as consistent as those on a sewing machine and again, the quality of the garment may suffer.
* What kind of fabric should I use for my costume?
Popular choices tend toward cottons, garbadines, lycra, dull satins, etc. Most people would recommend staying away from ultra-shiny satins (difficult to photograph well). Broadcloth tends to be frowned upon as well, due to its thinness, but when full lined or paired up with light interfacing or flatlined, it can hold its own.
* Can I dye (insert name) fabric?
As a general rule, natural fabrics take dye pretty well while synthetics don't take dye very well (if at all in some cases). For more specifics, view the linked threads above.
* Alternatively, can I bleach fabric to make the color lighter or to make the fabric white?
Bleaching out your fabric will give you one of two results: (1) damaged from from oversaturation of bleach or (2) splotchy bleach stains. Additionally, you can never be sure what color your fabric will turn once you bleach it. Remember those favorite black pants that now have pink spots on them from bleach? There is always the possibility of a dye remover, however. See linked thread above.
Need to add more! Make suggesstions! Continued below.