Ligatures and Line Spacing

Hello,
I have two questions.
1.) Line Spacing. It appears that I need negative line spacing. Because, when it’s set to zero, it’s setting the leading, the line spacing, to the same as the point size. I’ve got a small job here with 36 pt. type. With the line spacing set to 0, it looks very, very loose. I’ll literally have to break out its three lines into three separate text boxes.
2.) Ligatures. How can I turn on the use of ligatures in my fonts? Most of my fonts are OpenType fonts, so they have ligatures in them.

Thanks!
Peter