There are different types of electrical tape and different ways to stick it on.
I found 'Nitro' brand the best and you can buy it from most petrol stations.. If you look close at the top right of my first pic you can see the 'Nitro' brand.
When you stick it on start running it down the shaft about 4" above where the blade starts but as you stretch/peal the tape let it relax before sticking it down..and as you work your way around the blade just pull it enough to go on without wrinkles and try and keep it 50% each side as you go around the blade..and again as you get back up the shaft to where you stared from on the other side make sure the tape is relaxed before sticking it down.
Once you've done it a couple of times it gets easy.. Here's a couple of pics of mine.. You won't need to worry too much about rail bashing the Naish because they're so tuff.
DJ