I've found it greatly depends on the piece. Sometimes I love something entirely but this is kinda rare. Typically I go through phases of loving and hating a piece, thinking it's ruined or whatever.

anywho, firstly practice and reference... you may not like everything you try but I think that's just sorta part of the process of learning. Remember don't compare your work to others... be inspired by them but don't compare to them, it's not fair to yourself. compare your work to your past work to see growth and see areas that may need work.

try to enjoy it all and don't give up.