The most accurate way is an oscilloscope. Using a Fozgometer is second. My problem with it is the price. Both methods align the coils with the record not the stylus. If there is one manufacturing inconsistency that worries me most is the stylus not being properly aligned with the coils, an easy error to make. The above methods may result in the best sound but I prefer the least record wear so I use the mirror method lewm referred to above. That gives you a stylus aligned to the groove and you can't beat the price. I do add loops to the process.
Mike
Mike