Does vs do: when to use which?

imageA problem faced by most non-English speaking people while writing or speaking english is when to use do and when to use does.

The word ‘do’ is generally used in relation to pleural terms and with the word ‘I’.  Examples are as following –
We do not like cats.
They do not want corruption.
I do make sandwiches.
These books do not have a index page at the end.

Whereas the word ‘does’ is used in relation to singular things. Following are few examples –
He does not love oranges.
She does read novels in her free time.
It does not look good.
One does not need to be a doctor to do humanitarian work.

Hope the above examples will prove useful.