I stumbled upon the method of going into small owner/operator shops when
they're busy and then watching (and most particularly listening) to the
owner/mechanic dealing with other customers. You can learn a lot that way,
particularly if you know a bit about wrenching and the other customer
doesn't. If you're really dedicated you can catch them talking to an older
woman. Some of those conversations will open yer eyes fer sure.
As to machine shops, I asked my local VW Jedi who he used/recommended. When
I got there the first thing I said to the guy was 'Hi, Jay recommended you
guys to me...', letting him know he was coat-tailing on Jay's reputation and
business, as it were. I've since decided after several years that those guys
are pretty straight-up anyway, but a gentle nudge doesn't hurt.

Cya,
Robert