Use to as a preposition before a noun or as an infinitive before a verb. To and Too can be tricky!
"Please take me to the dance"
"We don't need to buy that right now."
"You have to run every day!"
Use too as a synonym for also or to indicate excessiveness before a verb. Usually, if you can replace too with also in the same sentence, and it still makes sense, then you are using it correctly.
"I am going to the mall, too."
"I had too many tacos for lunch."
Use two to spell out the number 2. If you can replace two with 2 in
the same sentence, and it still makes sense, then you are using it correctly. This should be the easiest one!
"I have two hands and two feet."
"Can you give me two dollars?"