Start with the business problem
An ideal customer profile describes which companies are most likely to be a fit for what you sell. Begin with the problem you solve, the conditions under which it becomes urgent, and the people who own it. A list of industries is a useful filter, but it is not the whole profile.
Write down the difference between a company that can buy and one that has a strong reason to act now. That distinction will shape your research and your message.
Define the account and the buying group
Choose a few firmographic criteria such as company size, geography, or sales team structure. Add observable signals that suggest a fit: expansion, a new initiative, a change in leadership, or a known workflow challenge. Keep a separate list of exclusion criteria so your team can say no quickly.
Map the likely champion, decision maker, and people affected by the problem. The same account may need different messages for each role.
Test the profile in the field
Score a small sample of target accounts against your criteria. Ask sales which accounts produce useful conversations and why. Review replies, objections, and lead quality. Adjust the profile when evidence shows a mismatch.
A good ICP should help your team consistently decide who to target and who to leave out. Revisit it as your offer, market, and customer base change.