Value is making making hard things easy. If you can find the hard thing that someone wants to solve and make that easy, then you have created value for that person.
Think about it - what's the hard thing that your clients want you to solve? It is hard for technical reasons? or because it's risky to their career? What do they gain by solving the problem?
If, as a consultant, you're solving problems that anyone can solve, then what value are you bringing to the client? Are you more than just a commodity - more than just additional manpower and hours for the project?
As a consultant, I encourage you to evaluate the value you bring to the project, study to learn new valuable skills, and think about your value from the client's point of view.