If you think you're ready to market your music demo, think again. Make sure it's the best it can be, and it's the work of which you're most proud. Please don’t rush music that is unfinished, because a producer or a record label will be able to tell. Ask for feedback from random people - not your mom or best friend - and when enough non-invested strangers have given you the thumbs up, you're ready.
Have Your Social Media Presence Established
The music industry is more than just songs and videos. Marketing is a critical component of any industry that has a fan or client base. If you have personal social media accounts, keep them separate from your music. Set up business social accounts with your act name and branding, and make sure they match across all platforms. This is getting harder and harder to do. So even if you have no content yet, go get those social media handles before your name is gone! (While you’re at it, buy your website domain too. It costs less than a date to the movies.)
Do Your Research
Preparation is the key to success in any business, and music is no exception. Before you submit anything, find labels that specialize in your genre. Look at the labels of the artists you like or you feel have a sound similar to yours. Once you've found some companies you think fit your style, learn their submission requirements. Some, like Red Bull Records, have a simple online form. Others still accept CDs and flash drives by mail. Research each label's demo policies, to find out whether or not they accept unsolicited submissions. When I worked at Sony/ATV Music Publishing, we were bombarded by unsolicited demo CDs that never got heard.
Make individual submissions one label at a time. Some labels, like Protocol Recordings, give you a specific time frame after which you can submit your work elsewhere.
Be Instantly Catchy
Labels receive multiple submissions per day and don't have time to go through all of your material. The onus is on you to grab their attention immediately, like within the first 30 seconds. A catchy intro to your best song, matched with a professional internet presence, makes them want to listen and learn more about you.
No, not to spam people on Twitter all day. Utilize Soundcloud to send your music electronically to people individually with a special note catered to them.
Avoid the temptation to attach your demo to an email. This takes up space in the inbox of the person who is deciding whether to listen to your submission and if you make the process too cumbersome they might skip you entirely. Instead, provide a private Soundcloud link. Test the link first to make sure it works by emailing it to yourself before you submit it to the A&R manager.
Most important of all, keep trying even if you're rejected. A "no" is not a "never." If a label declines your submission, view it as a learning opportunity, and a chance to improve your process. Music is one of the most competitive businesses in the world, and as is true in many others, those who succeed are often the ones who try the longest.