Not building lookalike list. All of us must be having some customers. Some customers came inbound, few via referrals, few via word of mouth- it does not matter. What matters is that these customers are able to solve their pains with your product. Hence, once they are your customers- you should be "finding more of these". This is by far the most underrated GTM hack I have come across. There are few lookalike tools you can try- Ocean, Jesse (my product). While using these tools, you should be able to find out why certain new customers were surfaced- what were the logic behind these new suggestions, and then run a focussed outbound/ABM campaign on those list.
If someone asked you to list every person, contractor, and tool that can see your revenue numbers and customer data, could you do it without opening five different settings pages?
I couldn't, for a long time. We added people fast, handed a couple of contractors access to "just take a look," wired up some tools, and quickly didn't know who has access to what.