I struggle with doing eyeliner/eye shadow on my eyes in never really works out for me. Since forever, watching makeup eye tutorials, and practicing it I finally concurred the liner part. I think it really does take time. I definitely prefer a liquid liner verses any other types. But here is my favorite trick I learned watching all the videos that I can...
Map out your line. Start at the inner eye and place a dot, do this to both sides where your pupil stops, then dot your crease and dot the end where ever you would like your wick to end. Place the dots where the red dots are placed. Then connect the dots!
Hope this helped you, remember to keep practicing!
XX,
Lexi