We might not want to loose the focus off our music but if you want to succeed, at least until when you find once of those labels who will have somebody doing all this for you, then Marketing is your best option towards success.
Now, where should you invest in Marketing and what kind of Marketing should you be learning? I think in my opinion there are 3:
General Marketing: Perfect for you to learn branding and what it means to market yourself as a product, create that general image and that online respect you want to have so people will take you seriously.
Music Marketing: More obvious and related to the industry, this one will help you towards how to put your music in the right place and how to target the right people in the ways that will keep them with you forever.
You have some free learning blogs about it here: http://www.thealgorithmagency.com/music-studio/
Digital Marketing: More focused on Social Media and design for it, this is perfect to find new fans and to learn what not to do online!
Where can you learn all this?? So far after paying for tons of courses I believe The Algorithm Agency is probably the best for this, I spent money on courses that taught me nothing, I like how they keep creating and have real experience with artists like me! Also their courses are so far some of the most complete and cheapest out there, you can buy them in their Chuffed, https://chuffed.org/project/marketing-for-all