You cannot say that a kind thing is too small to have any benefit; neither can you say that a bad thing is too petty to do any harm. 

尽小者大，慎微者著；日就月将，学有缉熙于光明。- 荀子:《大略》

Accomplishing small things well is the way to fulfill great undertakings;   Paying attention to details is the way leading to success in  grand causes. Making progress each day and getting achievements every month, persevering in your studies, therefore gradually you will become clear-headed and sharp-eyed.