Tip #1: How to search only .org, .edu, or .gov sites
Sometimes you know you want to search for nonprofits (.org), government (.gov), or college/university (.edu webistes. Use site: to tell Google which domain (.gov, .edu, .org) you want to search!
Example 1: Autism Spectrum Disorders site:gov
Example 2: Aspergers site:edu
Tip # 2: Search in one specific website
Suppose you only want to see search results from a specific website or organization. You can do that too, using site:
Example: Autism site:ed.gov -- this searches for the word "Autism" within the Department of Education's web pages.