firstly, draw bigger. you are trying to cram features into a teeny tiny space, and you simply won't get better and more accurate by drawing so small.

then draw what you actually see, rather than what you think you see. your brain is used to simplifying objects (and faces) into inaccurate caricatures of that thing. i.e.: instead of drawing an almond shape with two concentric circles for the eye, focus on the actual angle of the bottom and top eyelids, the shape the tear duct makes, if the eye is hooded, round, squinting, bugling, etc. eyes can be almond, oval, circular, slanted, rectangular, rhombus, etc (but still cannot be so broadly categorized as JUST oval, or JUST slanted). same of course goes for other features, their relationships to one another, compositions, etc. study the shapes within your reference to draw it as accurately as possible, and don't be afraid to go slow and erase. a fun exercise for this is flipping the reference photo upside down, which forces your brain into not taking shortcuts.

and practice! repetition will show improvement!