Okay, I know what you're thinking. Fashion faux pas. But I think 1) there are no fashion faux pas, wear what you want. and 2) mixed mediums is perfectly acceptable.
I've been thinking about more ways to wear a single color lately, by either breaking it up via texture, or by adding accessories that keep the flow of your outfit interesting. There are plenty of silhouettes you can play with too when sticking to a color "uniform".
I wanted to keep this casual, this is something I would wear when hanging with friends, and it could easily be styled up by swapping out the oxfords for a pair of heels, swiping on a red lip and pulling your hair down. Shades are a must, always.
suede bomber | mango
chambray button down | gap
denim | uniqlo
patent oxford slip ons | jessica simpson
chain bracelets | h&m
shades | found em on the ground