A great alignment tool, almost impossible to fudge, is the Mobile Fidelity Geo Disc. I use it myself, and it works wonderfully.
Now Azimuth is more difficult... What people say is that you should use a small flat mirror and make sure that the cartridge body and stylus reflection seems perfectly straight.
You can always do it with test equipment, in fact there's a unit called the Fozgometer: http://www.needledoctor.com/Fosgate-Fozgometer-Azimuth-Meter
You can also do it by ear with a test record.
In my experience, the best result can only be found with test equipment or by ear, and sometimes the mirror method isn't as effective as one would like. YMMV!
