Thursday Bram at Freelance switch (http://freelanceswitch.com/author/thursday-bram/) writes an article on skills a freelance (but in general a client facing professional) needs to satisfy the client (full article at http://freelanceswitch.com/freelancing-essentials/learn-the-skills-your-clients-need).

Thursday says that “[...] As a freelancer, you’ll encounter two schools of thought: you should either specialize and make your name as an expert in your niche or you should diversify and land as many different gigs as you can. No matter which approach you feel is correct, though, developing new skills is critical.

If you’re an expert in your particular brand of freelancing, certain skills can help you support your position as an expert. [...]

If you’re taking a more diversified approach, the benefit of new skills may be more obvious. The more types of projects you can take on, the more work is available to you. [...]”

I agree on the approach, but I would like to add a bit of my own by suggesting a third kind of skills: Those “cross functional”, such as those relating to “interpersonal abilities” and those related to “strategic thinking”.

To be more clear:
a) interpersonal abilities are the kind of skills needed in any case in order to catch and deal with client needs. I think there’s nothing more awfull for a client to have a professional not capable of understanding a need more or less expressed, either if he professional cannot address it on its own.
b) strategic thinking is the skill and attitude of getting the bigger picture that exists at all levels (either if you have a real operational role and you’re using a professional to solve a specific problem, you appreciate having a wider view)

This post as a comment at http://freelanceswitch.com/freelancing-essentials/learn-the-skills-your-clients-need/#comment-54793