A color-block sweater already gives you a palette to work with. Pick one color from the knit for your shoes or bag, then keep the rest of the outfit simple.
With jeans for everyday wear
Pair a bright knit with straight-leg jeans and neutral shoes. Dark denim works well if the sweater already has several saturated colors.
With a solid skirt for dinner
Repeat the darkest color in the sweater with a solid skirt. If the knit is bulky, try a shorter cut or a small front tuck.
With a jacket when it gets cold
Choose outerwear in one of the quieter shades from the sweater. Try it on over the knit first so you can check for room through the sleeves.