I am guessing you are still in High School where you run the most basic routes.
This might some dumb, but it is the basic idea behind routes.
Just simply run straight 10 15 20 yards and cut in with your outside plant foot. Make sure to never ever round your cuts. After making cut, run towards the QB, never ever stop your cut.
This is very very basic, but it gives you a general idea.
Also, find someone to work with. Have some play as a CB to work on your hands and balance. Have them try to jam you. Practice by "hand fighting". Every route run by a WR is won because they were more efficient at the line of scrimmage.