Two other hints: 1) if the dough is too loose, pop it in the freezer for a half hour or so; 2) make them every week so that you get the feel for it. It takes several attempts before you know when the dough is the right consistency.
To make it right you need to use less flour and more "творог". And don't mess up tvorog with cottage cheese or some other western substitute. Buy it fresh in a good supermarket or farmers market, or do it your self. You can find some recipes here: co.uk