I usually pick a theme for an outfit and gradually build that up. For example, right now my mayor is decked out in green clothing and accessories, for spring. I think I'll do blue next, for summer.
My character was made a boy by accident because I put "Cool, right?" Instead of "Cute, right?" And laughed so hard that I completely disregarded the "I'm not a boy!" Option. I've been living with it fine, though. He's wearing a Wario hat, red, square glasses, a sweater vest, and blue sneakers. His hair is on the most casual setting, and the hair color is as blue as a clear sky!
I usually have my mayor's eyes covered at all times. When I started, I didn't bother to look at a face guide, and ended up with the worst eyes. I've put too much effort into my town to reset, so his eyes shall forever be shielded from the light; see no evil. Aside from that, I either go for formal or 'rock' clothes.
Currently has triangle shades, the white formal jacket, Slicked back dark blue hair, a 4-leaf clover for luck, and I can't recall what pants or shoes he is wearing.