So here's a quick rundown of when to use to, too and two:
- To: This form of to is a preposition, meaning it usually introduces a phrase. For example: I went to the store to buy eggnog. It is also frequently used as part of an infinitive, as in I'm going to eat lots of birthday cake Oreos or To boldly go where no man has ever gone before. If you are trying to write about your trip to the store or are using an infinitive, this is the word you need.
- Too: The word too is usually an adverb, which means that it is used to modify a verb or an adjective. For example: I was too full to eat coconut cream pie after stuffing myself with sweet potatoes. The word too is also used as a synonym for the word also, as in I, too, ate more fish tacos than I should have this year.
- Two: The word two is always a number and should never be used unless you are describing an amount of something or using an idiom (such as Lindsay has two left feet). Thus, the word two would be used correctly in this sentence: I have two pairs of red shoes.
To sum up: To should never be used as an adverb or a substitute for "also." Too should always be used as an adverb and never as a preposition. And two is always a number and doesn't ever substitute as an adverb or preposition.
I hope that made sense! I actually realized as I was writing this post that I need to be better about identifying parts of speech, because I had no idea how to describe how each of the different words functioned until I did a little research. :)
Enjoy your Wednesday! I've got a date with a big pile of laundry.