When you are moving to consulting role from development you need to understand that there is something else except pure development. This "something else" is rather tiny thing which may be missed easily.
If you look back to development or lead role your will see that the "product delivery" was the major area of responsibility. In consulting - it's absolutely the same, plus new "keeping the client happy" role :)

What does it mean for you?

Just forget about your technical readiness. No matter how you are good technically - it means nothing for client :) You need step above delivery into "meet client's expectations" position. It brings your to number communication between client's business holders to understand their needs and client's "massaging" (Chris I suppose it's your copyright) to rule the project into right direction.  You are becoming responsible to deliver your promises on time and control that everything is done.

There is a number of other items which mostly depends on your charisma and communication skills helping your being proactive with client. Your need to be heard by the client, bringing the clear understanding of what's going on. Heroic silent coding is the thing you must never do as a consulter on-site.

mirror: Wining the client