leads me to this post from Jim Lejeal on what makes a good director:

"aware of the legal fundamentals

duty of care

A quick definition of this rule is "the exercise of sound judgement and diligence". Said better it is defined as: A director must act as a "reasonable person" would under similar circumstances. So, a director must make a reasonable effort to make informed decisions".

duty of loyalty

Essentially this is the "interests of the corporation above self" rule. Said better it's defined as: A director has a fiduciary duty to act in the best interests of the corporation. The director must set aside personal, financial, and professional interests when making decisions for the corporations. Directors should avoid any appearance of self-dealing.

motivated

genuinely interested in being on a board. It's not a title thing and should not be for the purpose of resume' padding. It's work. And you/tehy should be interested in working.

genuinely interested on what the role of a board member is. Have they studied or read about the profession (is it a profession?). What's their interest in taking the role?

proactive

16 hours versus 6. Best practices suggest that a good board member doing the minimum will put in about 16 -- 24 hours a month. I have worked with a board member that didn't. She came to the meeting unprepared, unhappy, unsettled and unprofessional. She was disheveled, disruptive and disappointing. She was a nightmare example of a board member and she taught me a lot about how NOT to act.

Critically thinking about the company and it's objective and strategy. You get it.

value add for the "stage"

early start up versus prepping for public offering. Again I think you get it. A board member is not a role that is one that lasts in perpetuity. In fact -- I think turnover -- perhps planned turnover - is healthy. Best practices supports this idea.

committee capable

able to and aware of serving as a committee member. This is part of being proactive and doing the job. Are they interested in the board charters? Do they understand the mechanics and schedule of a committee's purpose?

Skilled at questioning

This is by far one of the most important and necessary skills. Excellent board members -- not just independents are Black belt masters at the expertly timed and phrased question. I've
seen questions rolled out in the middle of the board table -- placed
timely in the meeting that materially and effectively value-add the
company to success and artfully move the conversation forward in a
helpful way and with shareholder value building effect. I've
also seen poorly phrased questions poorly timed bump and bounce onto
the board table and explode like a cheaply made WWII movie
hand-grenade. They explode -- everyone gets frazzled -- sometimes a few folks get hurt."