I think I got the hang of it my only problem is learning to sail back against the wind.
Sheet the sail in tighter and hike harder!
Seriously, that is the trick to going upwind. Don't be afraid to pull the sail in all the way and if the breeze is up, hook your feet under the hiking strap and lean out to keep the boat flat. Let the sheet out in the puffs so the boat doesn't heel too much. If it does, the rudder will come out of the water and the boat will spin into the wind (broach).
I sailed a Holder 12 a long time ago when I was young. They are a great little boat, excellent for learning.