Good advice.Terrance said:...
Study your design and other people's design as much as possible.
Also, don't forget to do your math. You NEED to make sure that the sump can handle all the water dumped into it in the event of a power outage (or you turning the power off for maint or feeding).
Keep in mind that overflows and sumps can be terribly loud (think toilet bowl), but there are ways to make them as quiet as a mouse fart.
Research, research, research...