This article is from the Martial Arts FAQ, by Matthew Weigel faq@idempot.net with numerous contributions by others.
- -You'll need some basic trust in the individual, as a beginning.
The instructor is the person who is going to be guiding your
development as a martial artist. You need to feel comfortable with
him or her, and feel secure in receiving instruction from them. If you
have some unease or personality conflict with the instructor(s) you
might want to look elsewhere.
- Do the students get personalized attention?
This will be a good judge of how valuable your time will be. If there
is a good amount of instructor to student attention there will be more
value for you.
- Does the instructor differentiate between forms and
function?
Another good indication is to find out if the instructor(s)
differentiates between form and function. In other words do they do
it "because it looks good" or "because it works." This may not apply
if you are looking for a martial art as a performance art or as an
exercise (though then you want to look at the efficacy of their
exercises...)
- Does the instructor(s) differentiate between tournament and
self-defense?
As above, your reaction to this question's answer will depend on what
your goals are. However, there is general agreement that tournament
training and self-defense training, while highly related, are
different. If the instructor does not differentiate the two - that may
be a danger sign!
- Violence in the class
If you see an instructor hitting students, or a senior student hitting
students, be very clear that it was appropriate before you consider
that school. Though be aware - if you are unfamiliar with the art,
medium or full contact sparring may seem overly violent to you.
Violence as discipline is to be avoided.
- Are adjustments made for students of differing body types
and limitations?
Another good sign is if the instructor adjusts the training of his or
her student's physical realities: telling a slow person to work
contact, a fast person to work ranges, a heavy person to work
leverage, a light person to work speed, or, conversely, concentrating
on their weak areas to compensate.
 
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