DON'T USE THE SANDPAPER STUFF!!! You will have no skin left on the bottom of your feet. 3M does make a grippy tape that is a textured rubber that works well but it's pretty hard to find (and pricy)

I've had great luck with the neoprene kit that Murray's sells - I put it on my 5.2 and my 6.0. When I installed it on my 5.2, I put it a little high and it wore where our butts dropped off the hull when going on the wire. I got smarter and offset it farther from the upper edge on the 6.0 - been on there for over a year and it's not showing any wear. You are supposed to apply the contact cement to the hull AND to the back of the neoprene before applying them and you are actually supposed to wait for the glue to dry. Then you put the two together and it sticks incredibly hard even though both sides are dry to the touch. Better put it on right the first time because it is NOT coming back off.