On the waterline I used a pencil and on the top I used gel. I prefer gel to liquid because it glides on smoother and dries quicker thus is easier to use and less messy. That's only because I'm hopeless when it comes to liquid liner though, if you can use it then stick with that.
So awesome! I am trying other things, I haven't broken out the gel yet but I found that if you use a pencil to draw the outline out, then go over it with another kind of liner it makes a really awesome bold clean look!
Sigma and MAC are my favourite brands and I kind of religiously use them, it makes it so much more difficult with crappy brushes. I also use nail art brushes instead of small pencil brushes because they're cheaper and a lot thinner.