I found this interesting blog post in Leading Answers blog.
To be truly effective you need ability and passion.
Some people use the formula:
ü Performance = Ability * Passion
However, you also need time to dedicate to the work at hand; and so Availability factors in also.
In the volunteer world we often say we are looking for 3 key attributes:
ü Talent (Ability in some useful skill)
ü Passion (motivation to do it)
ü Availability (time to commit to it)
In other words you need to have skills, enthusiasm, and time to dedicate to something in order to be effective. (This also applies to paid work too, but because we get paid for things it is easy to mix-up motivation with payment and forget about considering if we are passionate/motivated about the work.)