Hi Christina, not sure if you are you looking for launch marketing checklist or business side setup, seems both.
- setup a Google Alert for a product or company name, so you know when it's mentioned anywhere
- to monitor traffic in real-time and get notifications of spikes I would suggest to add ChartBeat
- for accounting I would highly recommend Outright - inexpensive and has all the basic features
- for marketing launch plan just google for blog posts - there are many on this topic
- I would test run your product through UserTesting.com before going after real clients - you could get some ideas and valuable feedback for last minute message/UI tweaks before launch
- have accounts setup on relevant (to your product) social networks and add links to your site, so anyone who falls in love with your product has a way to follow and/or promote you
The list above is a bit random, might help to narrow down goals and objectives.