Ever try directly using liquid liner to do that sexy cat eye or just your eye liner in general? It can be extremely messy and any time I attempt it, I'll blink and my eyeliner will be in the crease of my eyelid.
An easy simple trick is to first line your eyes with a pencil eyeliner. This will be your guide for whatever look you want to do. Then apply the liquid liner. The liquid liner stays put and it looks darker.