To create a website that is compatible on all different web browsers, you should use only standard compliant coding and you should not use proprietory HTML tags and features (these work only in the browser they were created for). Making your website look good in each different browser can be difficult because each browser interprets the coding differently, but checking how your website looks on each of the major browsers can help you get an idea on what code pieces will look bad on different browsers, and which to stay away from because of that.