I've been doing this for several years for Latin music and there's probably a book's worth of material on the subject. Here are some quick highlights on what I would do to help promote music.
Depending on the existing following, number of fans, touring schedule, album releases, etc, you have to mix up the strategies a bit.
I'm a big fan of social and incentives. Get the fans to work for you. Throw them links to free mp3 downloads or VIP passes for sharing or for signing up. There are some good contest apps out there that are low cost or even free. Try woobox
. Come up with your own ideas that are thematic, event related, and timely that can keep fans engaged and coming back for more. Cross-promote these things on social and drive traffic back to the artist's web site. Always be driving traffic back to their site as that becomes a valuable asset as the artist's popularity and traffic grows.
Post a lot of creative and sincere photos on Instagram and Facebook and Twitter and if there's another set of social tools that are relevant locally, then do those too. Grow that following and make sure that you're using the right tool for the right message and don't just spam all of those channels with the same stuff.
As for videos, play around with Periscope and Vine and use the video feature in Instagram. Hook that GoPro to the guitar or over those decks. Get a steady cam for the GoPro to make more professional looking videos. Generate a lot of content and keep it flowing on the artist's YouTube channel. New video, tweet about it. Upload it to Facebook too. I like using quicker edits on Facebook though, so you can catch people's eye and they're scrolling through their feed, so you might want to vary the video content for the platform. If he has a marketing budget to pay for some Facebook ads, then promote video posts. These are crazy effective and really cheap right now, especially if you do the targeting correctly. Running effective and efficient ad campaigns is pretty challenging, but you can grow your fan base radically with a pretty small budget.
Don't ever buy likes or fans. I shouldn't have to explain why. DO NOT DO IT. Ads are fine because you attract real people that are really interested in hearing some new music or seeing a great performance. Paying for followers is a waste of money and will backfire on you.
That's it off the top of my head. It should be enough to get you started and keep you pretty busy! Best of luck!