Prepositions – english.codeytek.com

In – areas, regions, cities, groups, liquids

Use for something that has borders and edges. ‘In’ is three-dimensional. So when you use it, you need to think about the position of something in relation to what surrounds it.

areas, region, cities
groups of people – ( except important high level groups where people are selected, e.g. He is on the board, They are on the commitee )
liquids.
Longer period of time – ( in July )

except important high level groups where people are selected

On – surfaces, rivers, oceans, lakes, a day

Used to talk about a position of something. ‘On’ is two-dimensional. For example, you have a flat surface and you are referring to the position of a person or thing in relation to that surface.

surfaces/ flat surfaces.
rivers, oceans, lakes. ( e.g. in the boat, on the lake )
a day ( on Monday )

At – specific places, public places, shops, addresses, events

Used for specific places or points in space. It’s one-dimensional. For example, when you are looking at a map, you are referring to a specific place or a position in space.

specific places, points in space.
public places, shops
addresses
events
One moment in time – ( at noon, at 9 everyday )

When we speak about something next to something, we use at.
When we speak about something inside space which is around something, we also use at.

Grey areas

In the below example, at the beach means, they probably reached the location of the beach, but not necessarily on the sand, they be outside.

In the beach means, they are definitely on the sands of beach.

By – next to something, beside or near.

To – direction, destination, distance, time b/w 2 pts, preference, limit, belonging

direction/ destination/ distance ( something is being moved from one place to another )
time between two points.
preference
limit or endpoint
belong (to)
ask ( to ) someone
travel ( to ) somewhere.