This is something I STILL have trouble with.
I found a video from Michelle Phan demonstrating how to apply pencil, gel, and liquid liner (this is why I love her).
Tip: Don’t pull your lids taut when applying — it can cause premature fine lines! I learned that also from Lost makeup artist Emily Katz, who told me holding it taut is actually counterintuitive since it causes more squiggly lines than preventing them! Her tip: keep your eyes open but downcast when applying!
What do you use to apply eye liner?