I used to have this problem also. A good trick is to take a pencil liner and line your eyes, then trace over it with the liquid liner.How do you put on liquid eyeliner without messing it up?
tap the brush on the edge of the eyeliner tube to get the excess liquid off, that will make it easier to draw a nice line
I have to have 0 caffeine and hold my other wrist as a draw. Start in the inner corner.
Try steadying your hand by placing your other hand under the hand you are using to apply the liner. Good luck!