I tried again a little today...it was not exactly a success. I think I need to take a day and just go for it..instead of one or two here and there...
Keep working hard at it. In summer 2009, I spent hours and hours trying to tack without success. In total, I must have tried a few hundred times, making very short runs, then tack, going back and forth so I would exercise both ways. It was only late in the fall that I started to get them more consistently.
All the advices posted here are, to my opinion, excellent.