It’s very likely that your business will call for a complete website redesign at some point. If search engine optimization (SEO) is responsible for driving a significant amount of of your business’ revenue, your redesign process may cause your company to lose your search engine rankings. This could be devastating and could even put you out of business.

The following is a list of crucial do’s and don’ts for preserving your SEO when redesigning your website:

1. Don’t change your URL structure. If you are going to redesign, do whatever you can to keep your URLs the same.
2. Do 301 redirect all old pages to corresponding new pages. A 301 redirect tells the search engines that you’ve permanently moved a page from one location to another. This is so that when your site comes up in the search engine results, people aren’t taken to a broken page.
3. Don’t have two versions of your entire site. Try going to your site with www and without (http://yoursite.com and http://www.yoursite.com). If you can get to both and your browser doesn’t automatically redirect one of them to the other, you have what is called a canonical issue. If your old site had www, then make sure your new site does as well.
4. Don’t overload on really heavy graphic elements; page-load speed is known to have an effect on your SEO. However small, you don’t want users or search bots to get frustrated downloading each page. Compress your graphics, clean up your code and keep it speedy, Jack!
5. Do delete the old site if your new site is on the same host. You never know how the search bots find it, but having a “/old-site directory” or similar is just never a good thing. Despite 301 redirects and all the above precautions, having your entire old site crawlable and accessible for bots or users is just a bad scene. Back it up locally or store it in a private folder on your web server.
6. Don’t trust your developers to do an SEO audit alone — they are way too busy with other things. If you don’t have an in-house SEO specialist or a hired SEO company, pay an on-site expert to audit your old and new sites with a fine-tooth comb. Although there are costs involved, if organic traffic is a revenue stream for you, it could become much costlier if your new site launches without the proper care.
7. Do have a robots.txt installed. This tells the search engine “bots” what to do. It’s a good idea to block out all the /admin, /dev, and any other directories or subdomains that you don’t want indexed by the search engines. Having useless, private, and duplicate pages indexed can dilute the strength of your entire domain. They are also a lot harder to remove once indexed then blocking them out in the first place.
8. Do have an XML sitemap once you launch a new site. Remove the old one from webmaster tools and from the actual live server. Then install the new one after you’ve got the site live and add it to Google Webmaster Tools and Bing Webmaster Central.
9. Don’t forget to migrate over all of your optimized title tags and meta descriptions from the old site. If your homepage had some good keywords in the title tag that was bringing you valuable traffic, the last thing you want is your new homepage title tag to be simply “homepage.” Even if that gets indexed as such for only one day, it could take weeks to regain your precious rankings and traffic from that kind of mistake.
10. Do ensure that you maintain good page text that is crawlable on the new site. Even if your old “ugly” site had a bunch of unsightly text, that highly relevant text was vital for your search engine rankings. Your new site might have a great design, complete with a Flash introduction, but for the search bots, there is absolutely no readable text on your homepage anymore. Make sure to keep readable/crawlable text somewhere in your design.
11. Don’t forget to install Google Analytics. If you had it on your old site, carry it over; don’t create a new account. You don’t want to miss out on traffic statistics, especially for a new site launch. Forgetting your Analytics snippet is common with site redesigns — but it could leave you blind to traffic and conversions at a crucial stage.
12. Do monitor Webmaster Tools crawl rates and other errors to ensure that you’ve covered your bases and that nothing fishy is going on once you launch.