Don't belittle yourself; you are more capable than you think.
Tips
usage
The fěi reading means 'meager, humble'. It lives in a few set words: 菲薄 (meager; to belittle), 妄自菲薄 (to undervalue oneself), and 不菲 (considerable, literally 'not meager', often of a price). The everyday fēi reading is unrelated.
Top grass radical. For the fěi reading the plant origin shows through: 菲 once named a humble wild radish, and from 'common scrappy plant' came the figurative 'meager, slight', as in 菲薄.
Bottom 非 gives the sound; the fěi reading is the same syllable with a different tone. It is purely phonetic, contributing no meaning to the 'meager' sense.