"In", "on" and "at" as prepositions of time:


At= Night, the weekend, the moment, the end.
In= Parts of the day (except night as was said), months, seasons, years.
On= Days of the week, dates


... As prepositions of place: 

In= House, things that are in some place, geography, garden...

On= Streets, directions, above something, 'on' a type of surface (road, wall)
 At= Home, specific position (door, bus stop, places of work).

A teacher of mine gave this table. I hope you find them helpful. 

In, on and at are prepositions of time and of place.  There are many different examples of how to use them.

I am at work.  We eat Turkey at Christmas.

I am in a taxi.  My birthday is in October.

The writing is on the wall.  My birthday is on 28th October.