This is the best place to start. First of all, you need to be as active as possible on soundcloud.
You want to upload your music as often as you can. Uploading every day is a great way to keep your audience engaged. Create a blog or a website where you post your music and create a link to it on your soundcloud profile. You can even set your self up with a twitter and facebook account.

The more social media you are on, https://soundcloud.com/ the better. Check out this article for more about soundcloud promotion .