Present Simple

Use
We use the Present Simple to talk about:

activities that we repeat regularly (routines, habits).
My mum and dad always watch my documentaries.

permanent situations and states.
I don't like going with groups. 

general truths.
The sun rises in the east.

Common time adverbials with the Present Simple: always, usually, regularly, every morning, often, sometimes, twice a week, from time to time, occasionally, rarely, seldom, once a month, hardly ever; neve/:

Present Continuous

Use
We use the Present Continuous to talk about:

activities that are going on at the time of speaking.
Right now she is probably giving a lecture. (now, at this moment)

activities that happen regularly but only for a limited period of time (temporary routines or habits).
I'm learning Chinese. (I'm having lessons but not necessarily at the actual time of speaking)

Common time adverbials with the Present Continuous: just, now, at the moment, at present.

Present Perfect

Use
We use the Present Perfect to talk about:

past events and activities with results or consequences in the present.
I've had some professional success. (I'm now well-established in my field)

a single or repeated action in the past, when we don't know or are not interested in when it happened.
He's lived with the Amazon Indians. (it doesn't matter when he lived there)

Common time adverbials with this use of the Present Perfect:
before, ever; never; often, already / yet (already in statements, yet in questions and negative sentences)

things that started in the past and continue up till now.
She's been a traveller since her mid-twenties.

Common time adverbials with this use of the Present Perfect: always, all my life, since/for

Since tells us about a point in time when the activity began:
We've been best friends since we were kids.

For tells us about the period of time that the activity has taken:
We've been best friends for years.