The short answer
Write down what you know against a qualification frame and the gaps become obvious. MEDDPICC is the common one: metrics they care about, the economic buyer, decision criteria, decision process, paper process, the pain you are implicating, your champion and the competition. If you cannot name the economic buyer or describe the paper process, you do not have a deal, you have an interested person. The single best test of a champion is whether they will do something for you, like get you a meeting with their boss or send you the security questionnaire. Be willing to disqualify early and loudly, because a clean no in week two is worth more than a maybe that dies in your forecast in month four.