At one time I made an insecure living selling consulting. I asked about problems and made suggestions. If the prospect liked the free suggestions he was persuaded to buy more for money. Sometimes a client became a repeat client, since I continued to inquire and propose while I was working there. Wherever possible I spoke to the president or general manager of small to medium size companies.
Chief engineers tend to see consultants as competitors.
Unless you are an expert in a narrow specialty, big companies do not need you. The public library has much data on companies which can help you make a prospect list. Always remember that the prospect has no interest in what YOU want. Click here for my full resume, engineering essays, and published and unpublished books, Index.