Just a couple of thoughts. Put in your meta tags as many pertinent keywords as you can. Make sure they really go with your site. Include the location, the type of restaurant, types of foods, anything else special and even owner names - anything people might consider when they search for this particular site. You need to think as if you are doing a search. You also need to think as not internet savvy people doing a search.
If there are other local sites that are likely to be well-ranked by Google - find out if there is anyway to get listed. Possibly a paid advertisement. But some may not require that. Does the owner have friends who will put links to his site? Maybe the newspapers' sites.
Another is to do a search of the local area in Google. There are tons of sites that lead to nowhere in someways - but would love links to anything locally. Not explaining this right. For example if I plug in my city and state - I get maineguide.com, city-data.com, hellometro.com, wunderground.com - and that is just Google page 1. So google clearly crawls these sites - and your listing might get bumped up by having these links in. Plus it might even bring in business.
While I am not saying this last one will work - I noticed that it helped me without intending it to. Showing your site in member sites here got a site onto Google pretty quick. Of course - the best part was getting good feedback and advice from the members here.
Another thing I thought of - if you have a site that Google spends a lot of time crawling - add some links to it. I would try to make them legitimate - like "here is my latest work." I took a web design course years back that was completely useless - and the teacher spent more time trying to show us how to scam search engines. I basically learned what not to do. So I never ever try to scam search engines because I read you can be penalized by search engines for it. (Not saying you are - just be careful by some advice you might find out on the internet on other non-RT sites that sound "wrong.") And definitely don't keep submitting your site to the same search engine.
And here are two newsletters I got subscribed to years back when I signed up for something else. I find them useful - but they send out lots each week.
http://www.webpronews.com/http://www.sitepronews.com/Please be sure to always create a "spam" email address for signing up for things as was mentioned by Franck. I lost two of my favorite emails to spam long ago - now I use the one that is less "educational" for my sign-up email address.
Also - if appropriate - have a good links page. It must fit your site of course.
Good navigation and content, in my experience, are the keys to getting onto search engines. Your site can look great - but if the content isn't there - then no point. Also make use of "alt" tags. And be sure you don't substitute a graphic for important content. Be sure the important words are at the top of the home page.
The advice I gave is what I used to create html pages and watch things climb google to page one at rapid rates. I am not sure if it is the same for Joomla - but SEO was kind of weird hobby of mine a few years back. Now I am looking to keep sites more "private."
One other thing - even if you aren't using Syndicate - going into the component Syndicate and put in your site's info. Be sure to remove any extra joomla content that might have installed anywhere else - newsflashes, newsfeeds, etc.
Good luck and let us know if any of this works. I am sure your personal experience will help others.