Follow and interact with people who have similar interests as you. The search function on Twitter allows you to find any topic you want and people buzzing about it. A lot of people go crazy with the ‘random following’ on Twitter, but simply following and engaging with people who have a similar interest can easily get you new followers/fans. Often times, when you follow someone new, they check your picture and bio first. Imagine if you were following a few people a day, and they all saw your amazing picture with your bio and link to your music!? You'd get hits and potential new fans. Take it a step further, follow people in the industry, network!
Encourage your fans to post about your music and shows. Instagram is a great place to get fans to be very interactive with your musical journey. This can include getting them to upload pics/videos/stories at your shows, and getting them to post hashtags about your brand. A great way to do this is to take pictures with your fans! Another great way that music artists get fans buzzing about their music is to run giveaways and contests on Instagram that involve fans posting about the artist (can be anything, i.e: a new song, video, album). You can Google and choose from a variety of "Pick Winner Generators" to choose your winner when giving away prizes and merch after getting your fans involved. Do this as often as you can!
Create in a space where a buzz is already present. People who have had the most success with music on YouTube are people who consistently cover/remake songs that are highly relevant to the music world. YouTube is very crowded, but it’s also one of the main places people go when a new topic hits the web. Use the traffic from popular songs, events, and topics to drive views to your video with all of the ‘related video’ marketing that YouTube does for its users.
Instead of giving away free downloads or adding "Buy Links" on your songs, try using Download Gates. Download gates are 3rd party applications and websites that hold your music for you, and when people request a free download of your song, they must first complete an action like following your Soundcloud page or leaving their email. This way, you can keep in touch with your fans and grow your audience while giving away music at the same time. The most popular Soundcloud gate sites include The Artist Union and Follow Gate.
Don't just post words on your status updates. Facebook is a tricky place. Because so many posts are getting published per second, Facebook curates the information on your timeline to only include what they think is the most relevant to the person scrolling their timeline. You have to kind of go with the flow in terms of finding what posts of yours get the most engagement from your friends and fans, depending on your audience. Have you noticed that the majority of posts you see getting the most attention on your feed include some form of media? Usually, pictures and videos tend to stick out and get more impressions. Get creative and see what works for you!