In general, you should enter search words in all lower case letters separated by spaces. You should never use commas, dashes, or other delimiters. It doesn't hurt, and it may help, to enter capital letters for some formal names. Most search engines ignore case, a few allow you to direct whether a search should be case sensitive, and a few will use case, whether you select it or not, to refine their search. If in doubt, enter the capital letters for formal names.
Some search engines are sensitive to the order of word entry.
In general, enter the more important or discriminating words first. If you don't get the results you are looking for, you might try changing their order to see if it produces a different result. Some search engines allow you to enter perl regular expressions. This can be a very powerful feature if you know how to do this. Other search engines allow you to enter very complex request using complex logic expressions.