My advice to anyone looking to hire a senior consultant is to read, if you feel compelled to do so, the management guru books and Harvard type studies then do one simple task. That is Enjoin the consultant into the issues facing you, be open and direct, set expectations, and listen to the experience. Besides the skills and experience, a seasoned consultant can bring to the issues a breadth of experience in industry with which to compare the issues and solutions. That alone can make the effort worthwhile.

Of course, if you are hiring a consulting firm to provide a number of MBAs to do a specific amount of work, guru books might be advised reading. As a consultant, I need management but my focus and work effort comes from the motivation of client success and being paid. If you wish to micromanage and set detailed goals for the consultant then you perhaps don't need a consultant. You thus should find someone in your firm that can recognize the problem/issues/need, can develop a solution plan, and take your orders. If you can infinitely define the needs, you must know what the problem is and in so doing are likely to know the solution. If you do not, at that point, perhaps you haven't defined the problem.  However, within this scenario an outside consultant's review or out of the box thinking can verify the issues and validate the solutions.

I mentioned earlier that deeply involving (enjoining) a consultant is the basis of good work and of a successful outcome. Success starts by first defining the expectations of the client. These must be clearly set forth. This of course must start by attaining an intimate knowledge of the issues the client is facing and to assure the client that the consultant has the ability to understand and work those issues. Beyond this setting of expectations a plan must be developed and the work must be done to the plan. Everything asked of the consultant must be fitted to the plan or the plan redeveloped. The amount of detail and number of milestones in a plan are very much dependent on the requirements and definition of the problem or solution.

Don't lie, or call it what you might, but not keeping the client informed is just that… a lie. If you set the expectations correctly this will not likely be an issue. Always deal with the client with straight up talk that includes solutions and risk analysis. Be flexible in your approach and be prepared to rethink and regroup or to say to the client "I am sorry this is beyond me, but I can recommend..."

It is the consultants duty to set realistic expectations of success and the degree of success. Not all problems can, at first look, be defined and an off the shelf/known solution found. The client needs to know that, and up front. If a consultant cannot convey this or set reasonable expectations he should not go any further with the client. Even within new product development a senior consultant because of experience and certain skills he possesses should be able to set realistic milestones in a plan. Cost overruns in these projects often occur because of technology or engineering unknowns, but these unknowns are still an upfront quantifiable risk. Most often costs become unmanageable because the expectations and deliverables were not established going into the project. Take time to develop a plan that is based on expectations, risk analysis, and deliverables.