a throttle curve makes the throttle less responsive within certain ranges. it takes some tweaking but what you want to try to do is flatten out the throttle curve around the point where your helicopter hovers. that makes the motors less responsive to small changes in stick position resulting in a less sensitive helicopter. there are likely thousands of forum posts on throttle curves for helicopters so just do a google search and make sure you let us know if you find a good one!
to be honest, my throttle is still linear as the HFP is easy to fly. tweaking the throttle curve is something that is nice to do but won't make or break your flying experience.
bart