You want to upload a bunch of new features and some bug-fixes to your site? Great! You want to avoid nasty side-effects and make sure that it works the same way like it was planned before? …then you will have to do a lot of testing!
Basically this Quality Assurance Phase should take place 2 times:
One time in a test-environment before the deployment to the production server and once again after the new web is live!
To maximize the efficiencies of your testing take care not to do the following mistakes that might lead to wrong observations, unnecessary time-waste or you will end up in overlooking faults: