1. Have some siblings (Perner, Ruffman, & Leekam, 1994)
Why? After spending a few paragraphs carefully ruling out a bunch of interpretations, they settle on:
“… as Dunn and Dale (1984) suggest, children do engage more frequently in creative social role taking with siblings than with anybody else. And since a benefit can be gained from joint pretence with a younger as well as with an older sibling, pretend play is perhaps our best candidate for a cooperative activity which furthers the eventual understanding of false belief.”
2. Having a Montessori education also seems to help (Lillard & Else-Quest, 2006). 80% of 5 year olds at Montessori schools passed the test compared to 52% at control schools. (A lottery approach was used to select who ended up at the Montessori school.) I wonder could the key advantage be mixed-age classrooms?
Lillard, A., & Else-Quest, N. (2006). The early years: Evaluating Montessori education. Science, 313(5795), 1893-1894.
Perner, J., Ruffman, T., & Leekam, S. R. (1994). Theory of mind is contagious: You catch it from your sibs. Child development, 65(4), 1228-1238.