Sandbox?? what's that? Preconfigure your site for the most difficult search terms and optimise your pages (not the site) for niche searches, then let it grow and use anchor text for high competitive searches (not starting with those before the site is about 3 month online).
After you buy your domain (make sure it is registered for 2 years or more) launch a "Website coming soon" page. have relevant content on the page, point a few links at it (Making google index it), then when your ready to launch your site, you should be GOOD TO GO!
Actually the best way to avoid the Sandbox is to register your website way before you build your site. Register your domain name once you have the idea. Make sure to have your site parked on a hosting account with the meta tags well optimized. A domain that is six months or a year old will make quicker results that if you just registered yesterday. Otherwise you just buy an old domain or register and expired one... BTW I don't think Sandbox has anything to do with how many years you register your site. Such factors are almost worthless for Google...