I read somewhere that the best way to tune is fret every string in turn to the same note, and tune to that note. Normally an E. Seems to work fine.

But normally I just use an electronic tuner, because that's a lot quicker. And it helps you spot which strings have gone out even in a noisy environment like a session when you can't even hear them too well.

Getting some decent tuning heads, preferably the individual sealed sort, can make a lot of difference to the ease of tuning.