Step 1. Know EXACTLY what you are looking for.
You can't vaguely look for "something about cars" and expect to get anywhere - unless you are in "just browsing" mode, the on-line version of mall windowshopping. You need to be looking for something - MPG rating of a Toyota Camry, or used car lot in Atlanta, for example.
Step 2. Phrase your search in the form of a question - either on paper or in your head.
I suggest on paper the first dozen times you do this. For eaxmple, "what is a current value of a 1967 Volkswagen squareback?".
Step 3. Underline the important words in that question.
current value 1967 volkswagen squareback
This gives you the keywords you'll use in the search engine entry box.
Step 4: Decide on the search engine and search type you need to use.
Most people, of course, like Google and Yahoo. I prefer Metacrawler, because it searches several engines for you, and returns the top results.
There are 3+1 search types: AND (require the presence of all the keywords on the webpage for it to be counted as a hit), OR (any of 'em will do), and PHRASE (has to have the words in that exact order to be counted). The "plus 1" refers to NOT (don't count a page as a hit if it contains this word).
Example: ford wagon "Oregon Trail" NOT car NOT engine NOT michigan
Step 5: Do the search!