OK, so we've established that you should look at the schools in your area. 
All well and good, but how do you _find_ what schools are in your area? 
Here are a number of recommendations.

- Recommendation of Friends - Ask your friends and associates.  You might
be surprised how many people you work with or shop with are martial artists
themselves or know of reputable schools, particularly hard to find "Garage
Dojos" (see the FAQ).

- Bulletin Boards at MA supply stores - It goes without saying that a local
martial arts supply store would be a good central location, a gathering
spot, for local martial artists.  They have to get their equipment from
_somewhere_. Look at the bulletin boards in these supply stores.  Don't
rule out general athletic supply stores.

- Bulletin Boards at Asian bookstores - Since many martial arts are Asian in
origin, many martial artists have an interest in Asian culture and books
(particularly books about martial arts).

- Bulletin Boards at Super Markets & the like - Many "Super Stores" such as
Wal-Mart and Meijers have bulletin boards specifically for advertising
within the local community.  These advertisements include bicycles for
sale, free puppies, and... martial arts studios.

- Bulletin Boards at Oriental Restaurants - Again, because many martial arts
are Asian in origin, many martial artists embrace Asian culture, including
Asian Cuisine.  More then that, it seems a likely place to put up fliers
for martial arts studious looking for a place to put up said fliers.  As
has been noted elsewhere, just because people working in these restaurants
are Asian, do not expect them to know anything about martial arts; some may
take offense at these sort of stereotypes.

- Local Colleges - Many colleges have martial arts clubs on campus.  Judo is
particularly well known on college campuses, but, by no means, has a lock
on it.  Some colleges even offer martial arts course for College Credit as
part of their Physical education curriculum.

- The 'Y', Civic Centers, and Community Centers - The YMCA/YWCA are havens for
martial arts schools.  Included in the mix are Civic Centers, including
religious based Community Centers, Park & Rec. programs and Police Athletic
Leagues.

- Classified Adds, free newspaper adds - Another source is in the Classified
Adds of your local news paper or in the classifieds of various "free"
newspapers, typically available in bookstores and groceries.

- Welcome Wagon Baskets - Many martial arts studios will include special
promotions in Welcome Wagon baskets to new members of the community.  These
promotions often include free classes, reduced rates, or free uniforms.

- Cultural Heritage Festivals - One of the common misconceptions is that all
martial arts are Asian in origin.  Though many of the most well known are,
there are an amazing number that are Occidental (Western) or otherwise
non-Asian.  Cultural Heritage Festivals often include a demonstration of
fighting arts from that proud culture, such as the Shillelagh from Ireland
or Gatka from India.

- Cultural Heritage Centers - The people there may know of schools, and in
some cases, might actually be holding classes of some kind in the facility.

- Renaissance and Western History Festivals or Clubs - Many Western Martial
arts such as Renaissance Combat Wrestling, Broadsword, Rapier, Bare Knuckle
Boxing, or Quarterstaff are often taught in clubs celebrating Western
Heritage or associated with such clubs.  One example is The Association for
Renaissance Martial Arts (formerly Historical Armed Combat Association)
<http://www.thehaca.com>.  The Society for Creative Anachronism
<http://www.sca.org> teaches some of these, typically in a "safe" "sport"
form but the local chapter can be a good place to start or they may be able
to direct you toward a school or instructor that can meet your needs.

- In the park - You might see an individual, or a group, practicing in your
local park. Even if you don't see any martial artists, if you chat to
folks, you might find someone who comes to the park frequently and has seen
a group that does practice there regularly.

- Local corporations - Many companies, especially larger ones, sponsor or
publicize employee group activities. These are not necessarily restricted
to employees of the company.

- Road Signs and Posted Advertisements - Most martial arts studios will put
up advertisements and fliers on telephone poles or at Mall entrances.  They
will also often put up "directions" signs pointing towards their school
from major roads.

- Yellow Pages under "Martial Arts" or "Karate" - As always, the Yellow Pages
has a section for those willing to pay for advertising their phone number.