There is some great tips in there in particular the tip to check how your website looks in other browsers is important. You can check what browser your visitors are using in your website statistics.
Here are some other thoughts if you are using google analytics then you can create a segment view for each browser type. This is very helpful as it can alert you to potential problems with browsers.
One simple things you could do is to sign up and review your site in the key web search engines - these provide tools for problem urls and give you clues to fix up problems and put in appropriate redirects.
The above three are the key search engines - you may want to also identify other specifically targeted sites of interest to your business.