If I have my kids in the plane, I don't notice the difference, if I have
somebody in the medium to large adult category there's a big increase
in sinkrate. I generally don't have any problem with it, but I probably do
a lot of little things to compensate (carry a little extra speed, and maybe
some power into the flare, etc).
Get somebody fat and take them flying, and do a bunch of takeoffs and
landings, that will help.
It's all about practicing the thing which you have problems with.
Jeff