Put that credit card AWAY. Purchases can be tracked so you BETTER have a good reason as to why you're buying rope, heavy duty garbage bags, and duct tape.

Alternatively, get some green bills out and pay for it all in cash, in separate purchases.

Get bigger shoes and stuff the toes with newspapers. That way your footprints look different than usual.

Have a spare set of clothes on hand, include a or coat so that you can get a different visual appearance away from the crime scene

Make sure the crime scene can't be traced to you. No family mountain cabins, no apartments or cars, no killing them at your place of work...yeah don't.

Don't tell anyone your plans; but make sure you know exactly what you're doing before, during, and after the crime. If the plans are written down, memorize them and destroy the plans immediately. Don't want anyone finding them. Oh, and don't even think about saving them onto a hard drive. All the plans better be in your head.