It would depend on the spirit, that's why most folks tend to turn to Goetic spirits as some of their various attributes have been recorded. If you're dealing with a new spirit, ask it what it can do and what it wants in return. Divining skills (pendulum in particular) are useful for this.
these are some introductions to high magic, evocation, conjuration, invocation, etc. a lot of it is kabbalah, but i feel it is a good starting point.
Oh sorry i didn't mention about the links. When you copy+paste them you must manually delete the spaces that "break" the link, the website has a function that disables links.
