I like to work in a sort of ABM-inspired outbound motion.
First understanding exactly who your best customers are and what they have in common, and using that to find similar accounts that you haven't converted yet. You can use tools like Sales Nav, ZoomInfo, Cognism to create a list based on what you learn from your existing customers.
Afterwards I like to build 2 sequences: one above the line, for C-Level/VPs, talking about the value you can bring to the company, and the other below the line for Directors/Heads/Managers, talking about the value you bring to their process (if both apply of course). Identifying 3-6 possible contacts in a company increase the chances of winning the account.
E-mail campaigns and LinkedIn outreach work best for me. Cold calling can work if done well, but I myself dislike it so I tend to not use it.