On answering written applications: GRAMMAR!! I can't tell you how often I've read an application and cringed at how lazy people are typing words correctly. I you can't be bothered spending 1 minute extra on joining the guild, what effort can they expect from you once you're in?
Secondly, Talent and reforge/gem choices are probably the most important factor in how recruiters determine a player's choices/playstyle right now. Especially when applying to a heroic raiding guild, knowing what the up and downsides of some talents are shows how well you know your class/spec.