Search Engine Optimization Tips:
Of course there are exceptions to this. Although, I have never had to pay for placement by following some SEO tips included here:
http://www.webdesignerforum.co.uk/index.php?s=4c38becb68f648e91ba31cad75891527&autocom=blog&blogid=117&showentry=190
Some of the basic tricks work the best. For example always include you keywords in your page title tag. Include Keyword in the image alt tag. Include keyword in your link title tag. And name your files appropriately. The web usually recognizes names with hyphens as spaces, so separate your words using hyphens to optimize your images (File-Name-Keywordword.jpg). Never put spaces in your file names! Use hyphens, and underscores.
Yes: New_File.jpg No: New File.jpg