"Every" is used when referring to all the members of a group of three or more (it is more usual for a large number). We use "every" to generalize and it is always followed by a noun.

Every house in the town is painted white.
Every girl in the class went to the party.
Every student deserves to receive the best education available in a safe and healthy environrnent.

We use "each" in front of the singular form of a count noun to emphasize individuality. "Each" indicates two or more people or things (more usual for a small number). "Each" can be also an indefinite pronoun replacing a noun. Indefinite pronouns refer to nonspecific persons or things.

Each test contains about 15 questions.
Give each child some chocolate cake.(= to each individual child)
You should make notes to help you remember each word separately. (= one by one)
Each employee was given a bonus. (= to each individual employee)
Each has a chance.

Last week it rained each day. (In this sentence we use "each" because the number of days in a week is limited.)
She has read every book in the library. ("Every" is used when the number is indefinite.)

"Every" CANNOT be used for 2 things. For 2 things, "each" can be used:
He was carrying a suitcase in each hand.

Remember that we DO NOT use a determiner with "every" and "each":

The each employee was given a bonus.
The every girl in the class went to the party.

It is often possible to use both "each" or "every":

Each/every time I see you, you look so fashionable.
There's a TV set in each/every room at the hotel.

We use "each of" before the object pronoun (you, them, etc.) or a noun with a determiner (the, this, my, your). The noun or pronoun is plural.

He'll charge each of you ˆ3.
They gave each of their children a gift.
Each of the audio lessons comes with a full transcript.
Each of the following sentences may contain an error.

"Every", but not "each", can be used with abstract nouns:

You have every reason to be happy with your new home. (correct)
You have each reason to be happy with your new home. (incorrect!)

We use "every" to say how often something happens (every week, every month, every year, etc.):
She plays tennis every sunday. (correct)
She plays tennis each sunday. (incorrect!)
They go on vacation abroad every year. (correct)
They go on vacation abroad each year. (incorrect!)
Trains leave every 30 minutes. (correct)
Trains leave each 30 minutes. (incorrect!)