1. Liquid Liner

Brush or Felt-tip, doesn't matter. 

What matters is how well you know how to use them and what kind of look you're going for.

Hard pencils (Not too hard though, we don't want them peepers to get wrinkles) and fast-drying liquid liners with firm brush tips, for me work best.

2. Mirror

Please, for your sake and mine, use a mirror.You can't "guess" when it comes to make-up and you don't want to end up like Lindsay here. 

As for me, I mostly do winged liners, since I have small eyes. 

I also do just the normal un-winged brown liner when I want just a little bit of emphasis on the eyes.