If your extension cord gets tangled up, don't pull on the ends. Instead, gently loosen all the tighter snarls in the middle until them become larger loops that can easily be untangled. A way to avoid tangles is to use a retractable cord reel. It will let you reel out only the amount of cord you need, then quickly reel it back when you're done.
When working near a sink or bathtub always put the plug in. This will prevent any dropped screws from entering the hole.