but i do understand it is hard to make a good portrait, it takes time and skill to perfect it.
i, for example, had most trouble with drawing actual lips. after some time, i got better at it, but i still fail at that segment sometimes.
one trick pretty useful in drawing portraits:
cover one half of his face with hand, then do the same with other half.
you will see that you drew his left side pretty good, but the right side is quite off. right eye is way too big compared to the left one.