Add flour gradually.
Check for dough consistency before adding all of the flour.
If dough is too dry, add 1 egg yolk.
If dough is too soft, chill 30 to 60 minutes.
You can substitute 1 teaspoon coconut and 1/2 teaspoon almond extract for the lemon or orange extract. The combination of coconut and almond is wonderful. Play around with the extracts and see which one you like.