It depends on what you have: point, an equation, or a graph.
http://www.google.com/search?q=how+do+you+find+slope&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
how do you find slope?
5 answers
graph
that weblink wouldn't come up
could you give me another link please? :)
http://campus.udayton.edu/~physics/lhe/HELPslope.htm