I find it very difficult to charge clients for "extras." In my particular case this is usually consulting and copy writing. Clients expect my input and often leave me with little to nothing to work with so I'm doing basically their sales pitch in addition to their deliverables. Sometimes they call me just to ask my opinion if a particular marketing avenue seems good or forward my contact information to a publishing company to work with them directly.
Us designers largely know that these are different skills but clients don't. They'll send me something like, "I need a flyer for a the 4th of July. Go to our website and include Product XYZ. Going to have Acme Co. print it out on some A4" --- no other information is provided.
For me especially this is problematic because my strength is probably about 80% in my ability to deliver very effective Messages. I could probably charge significantly more for my writing and consulting than I do for my design work. I just don't know how.
Just raising my rates seems very difficult because I don't feel many clients will understand the higher rate is because they're getting more from me than they would from other designers.
So how can I start charging people for that additional value?