Above all make sure that these keywords are also in your title tag which is that text that you can observe at the top of the page. The title is possibly the most critical part of your site from an optimization standpoint. Meta tags are of less priority now as compared to the other parts of your site, yet it is still a good scheme to comprise your primary keywords there in any event.
The description tag is a little more significant than the keyword tags but still much less relevant than the title tag. But write a high-quality description since this is the portion many people will see in the search results. When creating your Alt tags for your gifs and jpegs, be extra sure you do not place too many keyword phrases there since the search engines appear to be getting wise to this seo method and might possibly penalize your page for it.