A preposition is a word that links a noun, pronoun, or noun phrase to some other part of the sentence.
There is no definite rule or formula for choosing a preposition so its up to you to identify the right one and how it is used.
A preposition is used to show direction, location, or time, or to introduce an object.
Of
Used for belonging to, relating to, or connected with
(We always thought of buying a new car)
Used to indicate reference
(This is a picture of my best friend)
Used to indicate an amount or number
(I want three cups of coffee)
To
Used to indicate the place, person, or thing that someone or something moves toward, or the direction of something
(I am heading to the station)
(The message was sent to him yesterday)
Used to indicate a limit or an ending point
(The dishes were piled up to the roof)
Used to indicate a time or a period
(I will work at the store from Monday to Sunday)
Used to indicate relationship
(This article is essential to your job interview)
For
Used to indicate the use of something
(I made you a sweater for our wedding anniversary)
Used to indicate time or duration
(I visited Korea for only two days)