Song promotion, how to ?

[visheshl]

So my song Let's Go (Outer Space)
Is now available on amazon, spotify, etc.

Spotify

What id like is to promote it.
How do you all go about promoting your music?

Are Twitter ads effective?
Ads on Facebook?

Any good websites which actually help in promoting the song?
Any free services which can help put the song in playlists etc ?

Do tell whats been your experience promoting your music ?