As an absolute layman, here is a trick I was told and it seems to work well.
and it is borne out here
TACTICS ...
Use the windward rail for extra resistance. Stand forward of the straps, press on the heels to sink it, ...
If I am struggling to get upwind enough, once on the plane I lift my back foot out of the strap and bring it up so its right behind my front foot which is still in the strap.
seems to push the rail down just that bit extra and drives you upwind much easier.
Just have to be careful not to overcompensate and catapult