It's clockwise from the inside of the rim looking down from the nipple (top of the spoke)
You have to imagne that the tire is off your bike and you are tightening the spokes from the top (where the tube sits)... it's clockwise.
Where it gets confusing is if the tire is on the rim and you go to tighten the spokes on your wheel near the ground. It looks like you have to turn them counter-clockwise to tighten... Remenber "from the top of the spoke".
Hope this helps