We have a whole bunch of resources set up for you ;)
https://www.ifixit.com/Device/Pro_Tech_Network
https://pro.ifixit.com/
In terms of tools, we offer a [https://www.ifixit.com/Store/Tools/Repair-Business-Toolkit/IF145-278?o=13|repair business toolkit]—and there’s an option to save some money by leaving out the Pro Tech, since you already have one. In addition I would recommend:
* Heat gun
* Heat mat
* USB ammeter
* iPhone screen programmer
Those are the items I’d want to have on day one, but there’s a lot more to add as you increase your skillset and broaden the range of repairs you offer. A microscope can be really helpful for finding board damage; an ultrasonic cleaner is invaluable for water damage repairs. If you plan to do any soldering or microsoldering, that’s a whole other bag of jacks. There are lots of specialty tools for various categories of repairs, like the opening wheel and service wedge for iMac repairs. Read lots of guides and watch how-to videos for the repairs you plan to do, note what tools people are using, and go from there. Good luck!