A couple lessons I've learned:
1) An ad in the paper for help is an admission of guilt by a company.
Guilty of not being able to grow their own mechanics...
or guilty of not being approached by good prospects based on word of mouth.
2) Don't waste your time looking for a job from anyone who you don't KNOW already has a need for help.
Several years ago I was on an extended road trip all around the US interrupted by short term gigs to replenish my wallet (I'm not independently wealthy). During this exercise I learned a few things about finding potential employers in a town where I had zero reference to know who was who.
(And I learned how to interview with them.)
I'd arrive in that town on a Sunday afternoon and get a copy of the Yellow pages but I didn't look for the EC's... I looked for the supply houses. After mapping out their locations I'd plan a route to be able to hit 2 or 3 way, way bright and early on Monday morning.
Show up at the supply houses (dressed to go to work that *minute*) and take a minute to look around (there is often a bulletin board there with open jobs) see if their stock (and tools) represent the sort of work you prefer to do (eg rexel/romex vs graybar/rigid) and listen to the counter droids talk to a few customers to gauge which one might actually have a clue about life.
And then look ask politely:
which contractors in town are busy...
who has been buying a lot of stuff in a disordered way...
who has actually complained about needing help...
Assuming you get a positive reception try to find out who at the EC is the one who actually makes the hiring decisions (no one else counts!).
One of the EC's in there to buy material may even have a job for you.
Take careful notes, listen!, get the counter guys name, etc.
Then make the call(s).
Yes sir! I'm right here at XYZ Supply and Dave said I should talk to you. I understand you could use some help and frankly sir, I could use the job.
When he asks you a question answer accurately, never overstate your experience, and by all that is holy NEVER lie to the man.
If you don't have experience in X (but have the right attitude) he'll most likely give you a shot.
At some point the money question will come up.
(If he has any sense he won't ask until he sees you in person)
How much pay do you want?
In good times (with experience):
Well sir, of course I want as much as I can get.
If things are tight (or little experience) then offer:
I'm willing to let you decide that after we've worked together for a day.
I might have had to repeat the supply house routine a couple times and the intro phone calls too but more often than not I'd have a job by noon.
Good Luck.