I'm terrible at makeup myself, but I got a great tip from someone once about eyeliner. I have hooded eyes and they're sensitive, so my lids twitch involuntarily as soon as they're touched by a brush so I gave up trying to do anything precise.
The tip I got was to get a soft kohl or mineral eyeliner pencil, and rub it on to my lash lines, being as clumsy and messy as I want. Then go in with a fine soft brush and use the brush to rub it in and smooth it all out and get it closer to my water lines. It doesn't wear that well on my skin, maybe because I refuse to buy the "good stuff", but it looks fantastic and way better than any of my previous efforts at sharp looks.
