Don't be afraid to buck tradition

Animals in a car

Recognize diversity in sites.  Some are bigger, some are smaller.  Some are formal, some are loose.  Some need to be reliable, some need to be cheap.  Everybody has different needs, and almost nothing is going to be true for everybody.  Use what makes sense for your site, and break the roles that don't apply to you.

Don't be afraid to break "best practices".  Technology changes very quickly, and yesterday's best practice might be obsolete tomorrow.  While it's great to stay abreast with standards and practices, don't view anything as a hard-and-fast rule.  Be ready to change and make exceptions.