Short answer: Just good enough to convince a client you understand and can solve his problems for a reasonable fee. Check out Alan Weiss, always has excellent

Short answer: Just good enough to convince a client you understand and can solve his problems for a reasonable fee. Check out Alan Weiss, always has excellent material on consulting> http://www.amazon.com/Million-Dollar-Launch-Kick-start-Successful/dp/0071826343/ref=sr_1_sc_1?ie=UTF8&qid=1405697242&sr=8-1-spell&keywords=wiess%2C+start+a+consulting+business http://www.amazon.com/Million-Dollar-Launch-Kick-start-Succe...