The present continuous is used to talk about present situations which we see as short-term or temporary. We use the present simple to talk about present situations which we see as long-term or permanent.
In these examples, the action is taking place at the time of speaking.
- It's raining.
- Who is Kate talking to on the phone?
- Look, somebody is trying to steal that man's wallet.
- I'm not looking. My eyes are closed tightly.
In these examples, the action is true at the present time but we don't think it will be true in the long term.
- I'm looking for a new apartment.
- He's thinking about leaving his job.
- They're considering making an appeal against the judgment.
- Are you getting enough sleep?
In these examples, the action is at a definite point in the future and it has already been arranged.
- I'm meeting her at 6.30.
- They aren't arriving until Tuesday.
- We are having a special dinner at a top restaurant for all the senior managers.
- Isn't he coming to the dinner?