The title of your web page carries the most importance with search engines. Don't waste this by using something like "Home"! The title metatag should be below 60 characters and include your most important keywords first, if you have a company trademark or trading style then you might want to add this to your description and keywords list too.
This tag is often used by search engines to obtain a description of the web page. It may not affect your ranking, but it is the description that search engines such as Google put in the list of pages found in a search. The description should be an accurate description under 160 characters that will attract visitors to your page. Ideally it should contain words and phrases that are part of the page content, but make it meaningful - getting on the search list is one thing, but the key thing is to get the searcher to visit your site!
Keywords are words and phrases separated by commas, generally with no spaces after the commas that someone looking for your site might type into a search engine. Generally aim for 5 to 10 words maximum. Google will generally ignore keyword metatags, but other search engines may use these to help index your website and any internal search method on your site may utilise them.