Pull your credit report.
Call and close any inactive accounts you see on it.
Get on the DMA's "dont mail" list
https://www.dmachoice.org/onlineform.php
Have the three credit bureaus stop selling your information
https://www.optoutprescreen.com/?rf=t
Call each bank/credit card/insurance/other financial company you WILL be doing business with and tell them that you are opting out of all information sharing with all other affiliated businesses, internal and external, and opting out of all communications except for matters pertaining to account security.
This stopped it all for us. No offers of credit, no unexpected credit cards, no calls, no junk mail, and a lot less opportunity for fraud.