I see with "view source" that you don't use many balises "méta".
I know that some of them are totally needless but I think you should use the balise
<meta name="revisit-after" content="15 days">
(Above all you should not write "1 day", 15 or 30 days is better and commonly used)
It's not a good reference but you can see all the list of méta at this website
www.referencement-team.com/metatags/liste-meta-tags