Anyone remember this thread out of Bonnie/T-100
Pretty much everyone will say the "ping ping plunk" test. You flick each spoke with your finger. Personally I tap each spoke with a screwdriver for the correct sound and tighten up accordingly. If it goes "ping" it's good, if it goes "plunk" you need to tighten it a smidge then retest. Rinse and repeat for the whole wheel, front and back.
Get a wrench which fits the nipple snugly. Rap the spoke with said wrench. Listen. It should ting. If it tunks or is just duller sounding, tighten. Work around the wheel in 120 degree bites.....count 13 nipples and check that nipple; then thirteen more. Keep going around till done. This will keep you from getting the rim out of truth.
Dr Lapo - the nipple wrench size is 5.9mm or a #8 spoke wrench
at 4000 miles most spokes on my Thruxton required a 1/16 turn to snug them up. They are a right hand thread = righty tighty. The wrench that comes with a KX250F works so a dirt bike shop may be a good source
I have 30 years + worth of bike tools so the 5.9mm wrench has been in my tool box for a long time. A 6mm wrench is loose so be careful as the spoke nipples are soft, a #8 wrench fits too but I do not know where the "Title" #8 comes from; its just marked on the wrench (the other end is a "9")