Cut your garment according to your cloth.

Literal

Cloth [to-に] accordance-with clothes [object-を] cut [imperative-裁て].

布に応じて = 'according to the cloth.' 裁て is the regular imperative of 裁つ ('to cut/tailor'). 衣服 is a formal word for 'clothing/garments.' A proverb meaning to work within your means.