I like the 3 characteristics wiki has for tomboys:
- The wearing of typically masculine-oriented types of clothes.
- The practice of games and activities (often physical in nature) that are typically considered to be the domain of boys.
- Heterosociality, the preference to befriend boys rather than other girls.
STPs might be more likely to take part in male dominated sports and activities, while NTs might just befriend boys more often than girls and not adopt a real feminine dress code.