You can do it wet with a angled brush for a more defined line or dry with the same brush for a soft liner effect. I also use the product She Laq from Benefit and mix a drop of it with a bit of loose eyeshadow and it turns into liquid liner that lasts all day. If you're going to use the brush wet be careful when picking the e/s from the pan as it may get crusty in that area. HTH
I use an angled brush with a little eyedrop solution but at work we just use makeup remover. You would think it would ruin the shadow but it actually works really well.
i use an angled brush. i apply the e/s dry if i want to smudge the line, or i just wet the brush for a more defined line. you can also use a pointed brush, it's your personal preference.