Use the Present Continuous:

to talk about things which are happening at the moment of speaking

I am writing this. (now)

You are reading this. (now)

He is watching television. (now)

They are running for the bus. (now)

to talk about things which are temporary, happening around now, but maybe not at this exact moment:

He is working in France this month.

She is looking for a new job.

We are trying to save money.

They are reading Harry Potter in English classes.

We often use these words with the Present Continuous:

now, at the moment, today

You are reading this now.

He is watching television at the moment.

I am teaching today.