Look under the subject areas to find a foundation match for your project. You can also look under types of support, for example program development, operating funds, start up, etc. What you don't not want to do is go to a foundation that does not fund in your area. This is a waste of time. It is also very important, whenever possible, to have direct contacts with people in the foundation.
Someone always knows someone.
All it takes is enough of a contact to get your project off the rejection pile and onto the maybe pile. Try to find a way to go to the foundations to explore your idea first before you even get to the time-consuming point of writing a grant. It usually takes around 100 hours to draft a proposal to a major funding organization, but it may take less than 10 hours to assemble a proposal to a local foundation with less stringent submittal requirements. The Foundation Center has all sorts of information, as well as publications. Besides foundations, you can also look at associations that have the same interest as you, for example, art or architectural associations.