"Meta Title" is the name of your page in search results. Try to incorporate your most important keywords, but keep it short.
"Meta Description" is the block of text that appears below your site on search results. The search engine will cut it off after so many characters, so it's best to keep it short, focus on the most important information, and include key search terms you want people to use to find you.
"Meta Keywords" is a list of key search terms you expect people to use to find your site. They are a hidden part of your site's source code, so they don't have to look attractive. Seperate keywords with commas.