Social media is the best and the easiest way to promote everything and anything you’re doing. You should be intelligently using Twitter, Facebook, Instagram, and whatever other platforms you’re on to shill everything from new albums to video content, concerts, merchandise, and so on.
If you don’t want to get too involved in hashtags and other endeavors, I’d suggest you start by simply posting promotional items at different times of the day. It’s a no-brainer to tweet about a new video when you and your friends who live in the same place are most likely to be online, but what about those who love your music all the way across the world?
You should be using some sort of program to pre-plan posts on platforms like Twitter and Facebook (some sites like Instagram don’t allow for planning uploads), and you should go out of your way to schedule things to go up when people in other countries are most likely looking at their feeds. If you only post during the same hours every day, it’s likely plenty of people who could be interested will never get a chance to see what you’re saying.
You are more than welcome to literally copy and paste the same tweets and send them at different times of day, but you might want to put in a little bit more effort than that, which really is the minimum. Come up with different ways to say the same thing, and maybe send out similar messages on different days, not just different times.
You shouldn’t invest tons of time into something like your Twitter page, but keep in mind if your fans see you posting the same few tweets over and over again, you might lose some of them as followers, and this has actual consequences (beyond lower numbers on your profile).
Also, look into what hashtags are popular in other parts of the world. Are people using a certain hashtag in India to talk about rock music they just discovered? Maybe there is a new one in Japan describing just-released EDM that’s about to break. These hashtags can be great ways to get into the conversation, especially if they are in any way regionally-specific.