learn the rule: to / too

  • to is a preposition, indicating direction or attachment to something
    • Your sock is next to the potato.
    • Who did you give your potato to?
    • Where's he to? (Westcountry usage only.)
  • too is an adverb, generally used as a sub-modifier
    • Are they doing it too?
    • You're too ugly.
  • The two are not interchangeable.
  • Getting it wrong makes you look stupid. And ugly.