Using At, On and In

At, On and In (Place)

At 

At is used to talk about position at a point 

example:

Its very hot at the center of the earth. 

Turn right at the next traffic lights.

Sometimes we use at with a larger place. If we just think of it as a point: a point on a journey, a meeting place or the place where something happens.

example:

You have to change trains at Dehli. 

The plane stops for an hour at Bellary.

Lets meet at the station.

There's a good film at the cinema in car street.

In address, we use at if we give the house number.

example:

She lives at 72 Albert street. 

ON

On is used to talk about position on a line.

example:

come on supper's on the table.

I'd prefer that picture on the other wall.

There's a big spider on the ceiling. 

We say on (and off) for buses, planes and trains.

example:

He's arriving on the 3:24 train.

We use on for the number of the floor.

example:

She lives  in a flat on the third floor.

IN

In is used for position in a three dimensional space (when something is surrounded on all sides)

example:

I don't think he's in his office.

lets go for a walk in garden.

I last saw her in the car park.

We use in of we just give the name of the street.

example:

She lives in Kuvempu street. 

Learn these expressions:

in a picture, in the sky, 

on a page, in bed/hospital/prison/church/temple/

at home/school/work/university/college

At, On and In (Time)

Exact times

examples:
I usually get up at 6 o' clock.
I will meet you at 4:23 pm.
Phone me at lunch time.

Parts of the day

example:
I work best in the morning.
Three o' clock in the afternoon.
We usually go out in the evening.

Exception : At night

We use on if we say which morning/afternoon etc,.
We are talking about or if we describe the morning / afternoon etc,.
example:
See you on Monday morning.
It was on a cold afternoon in early spring.

Days

example:
I'll phone you on Tuesday 
My birthday on May 4th.
They're having a party on new year. 

In informal speech we sometimes leave out ON (this is very common in American English.) 
example:
I'm seeing her Sunday morning. 

NOTE : The use of plurals (Sundays, Mondays etc,.) when we talk about repeated actions.
example:
We usually go to see Granny on Sundays. 

Weekends and Public Holidays.
We use at talk about the whole of the holidays : at Christmas/ New year / Easter etc,.
example:
Are you going away at Easter?

We use on to talk about one day of the holiday.
example:
It happened on Easter Monday.

British people say at the weekends ;  American use on. 
example:
What did you do at the weekend?

Longer Periods
example:
It happened in the week after Christmas.
I was born in may.
Kent is beautiful in spring.
He died in 1998.
That house was built in the 15th century. 

Expressions without preposition: 

Prepositions are not used in expressions of time before next, last, this, one, any, each, every, some, all.
example:
See you next week.
Are you free this morning.
Let's meet one day.
Come any time.
I'm at home every evening.
We stayed all day.

Prepositions are not used before yesterday, the day before yesterday, tomorrow, the day after tomorrow.
example:
What are you doing the day after tomorrow.

At all

We often use at all to emphasize a negative.
example:
I don't like her at all.(= I don't like her even a little.)
This restaurant is not at all expensive.

We also use at all with hardly ; in question ; and after if.
example:
She hardly eats anything at all.
Do you sing at all? (= Do you sing even a little?)
I'll come in the morning if I come at all. (=perhaps I wont come)

NOTE : We can say not at all as polite answer to thank you.

Correct using Article A AN THE