I always put them to the left of the wheel where you can easily reach it---I can activate my own without having to take my left hand from the wheel (it's actually a momentary rocker switch that triggers an electronic self canceling module). Here's a photo of one that I built for a customer that uses a momentary toggle for module activation:



The first switch left of the speedo is turn signals, the other one farther to the left is high/low beam toggle.

Jeff