Sometimes you do a better job of measuring things when you're cooking just by eyeballing it rather than taking the time to actually measure everything.
この場合、次のような言い方ができますよ。
ーSometimes you do a better job of measuring things when you're cooking just by eyeballing it rather than taking the time to actually measure everything.
「目分量で料理する方が、時間をかけて実際に測るよりちゃんと測れていることがある」
to cook by eyeballing ... で「…を目分量で料理する」
ご参考まで！
カナダ 
