1) take some straps off of your pole grips, there is usually a screw on top, undo it, then pull the strap out.
2) acquire small "spring toggle"
3) make hole in both strap and top of grip just big enough for the toggle to fit thru.
4) align the strap on top of the grip then insert the spring toggle through both.
5) turn the bolt that will be sticking out the top with screwdriver until its tight. (you may want a washer between the top of the bolt part and the strap)
background info: spring toggles work by having the two "wings" fold upward as you insert it. once it gets through to an opening the "wings" will open up inside of the grip and hold the strap down once you tighten it.
pic of a spring toggle: