You will not likely work directly with the CEO on any project or product purchase; you will be referred to the appropriate person. The information you gather on others should be the same as the information you gathered on the CEO. You will need to know the personality type to give you that inside edge, and also how much influence they have on the decision to make a purchase; you may find that these other contacts have an authorized spending limit following a set of guidelines.
You want to make sure you target the correct person once the decision is made. These contacts will often have an inside edge on up-and-coming projects where you might be of use. They may even get additional funds in order to buy from you. I had a client that was limited to $10,000 on any purchase order, and my services for the quarter were to be $32,000. Instead of having to fill out the paper work and get additional approvals, he simply made four separate contracts for me, each with their own start dates, milestones, and project completion time. It worked well for him as he did not need additional approval to continue the project, and it also worked for me as I was paid in a shorter time frame than otherwise.
Having a person in the company at the right level for approving projects and purchases will make a difference between making the sale and knocking on the next door. You need to form a close relationship with that person and make sure they are completely satisfied with your work.