How do you level your turntable?

I use a 12" carpenter's "torpedo" level.

Ya gotta level your platter to the best of your ability. When mine was off about 1/3 bubble, I was getting the weirdest phase anomalies and balance problems. On one mono album, the sound seemed to come from from the front window to my left--90 degrees left of the point between the speakers.

Using my trusty Sears Craftsman level to get the bubbles to level longitudinally, laterally, and diagonally fixed all this.

I have a linear TT (LT-30) and am another who uses the Sears $25 digital laser level.

1. Level stand
2. Check TT from platter and base
3. Sit back and enjoy, and do not check again unless I need to

any good bubble level is fine.

I used several long levels (two 4' and one 2') to check the accuracy of three 12" ones. (One of those was actually out a little.) The accurate ones are used to level the platter. Once that is done, I permanently mount a pair of custom made glass vials into the plinths of my turntables, so the user can keep an eye on it all along. To me, levelness is a big deal.