The swipe gesture for accessing Notification Centre is the same as for going back in Safari (amongst others). How can I consistently get it to do one or the other to stop me using the wrong gesture?
Put two finger on the right side of trackpad, your finger should be outside of trackpad area.
It works beautifully for me.
I created video how to do it, you can see it here http://www.youtube.com/watch?v=4znRZBAtE1s
You might wonder why a two finger gesture on the trackpad from the right edge to the left edge doesn't always allow you to quickly access the brand new Notification Center in Mountain Lion.
Apple's instructions state:
What they actually meant was a swipe gesture starting from the very edge if not outside from the right side of your trackpad and then finishing on the left side within you trackpad. This is easier on a notebook trackpad, you can start on the wrist area and swipe in, it's harder on an external one tho.
If you start too far within your trackpad you won't be able to perform the gesture for quickly accessing Notification Center, or you will trigger the page forwards/backwards gesture instead.