I have a love- hate relationship with eye liner. Somedays liner make me feel beautiful and other days it makes me feel like I'm as attractive as a drunk raccoon that has shaved a lot of its face.
However practise makes perfect and thats what I did. Practise.
I was putting makeup on at age 4 and I was given my first liquid eyeliner when I was 12 because I had continually nagged for 8 years. xD
Now being 19 with 7 years of practise I realised it wasn't much different than doing your eyebrows. There are proportional guidelines you can follow to help you get your liner more neat and symmetrical.
First of all I had to accept that I was asymmetrical, like everyone slightly is. So if you're the perfectionist type, realise that having your liner a bit asymmetrical can actually work, if you know how to work with your features.
Outlining your lash line is the easy part. It helps if you pull the skin of your lid towards your temple to get a smoother and neater line.
The hard part is wings. I just go with the same preportions I follow when I am doing my outter brows. I start by drawing one line from my outter eye corner and I point them towards the tip of my brows, before joining the line back up to my lash line and smothing the liner to create a illusuon of an inward eye slant.
After I perfected this I started going nuts with this stuff..
Be creative guys!