The last couple days I've been asked and discussed with a couple broadcasters how to improve their streams, or, as I interpreted it, how to get more viewers. There is no one way, no absolute truth, but I've seen a few trends.
One of the most popular things broadcasters do is giveaways. Because who doesn't like free stuff? But this is a double edged sword. On the one hand, you'll get a lot more viewers, but these viewers will be of lower quality. Once it's over they'll either leave or pester you about your next one. This strategy works if you can keep up with the giveaways, but most starting streamers will be hard pressed to do even one. Giveaways at milestones for regulars is a good opportunity as long as you can weed out the ones who aren't regulars. Point systems are good for that with some minimal amount of points to enter.
The biggest thing that I've seen to be effective is networking. This means going to other channels, making friends, chatting, and helping out. Social media like Twitter, Instagram, and these days Discord. Like real life, it's not what you know, but who. If people don't know you exist, they can't show up. Host and raid the the people who have a similar types of communities, but don't expect them to return the favor. If they do, perfect. If they don't, try someone else.
I must at this point stress heavily that you should never self promote. Never mention you stream unless asked. Do not say you're about to stream when you leave to get started. Do not say you just got done streaming and thought you'd pop in. These kinds of things are considered rude by many streamers. You can ask technical questions if the expected answer is short. If you want to ask something general like "How do I get started?" or "Can you help be get the settings right for OBS?", these things should be asked off stream, preferably Twitch message or Discord. Whispers is not a good medium for that. The basic idea is, do not interrupt them for your personal gain. Respect the broadcasters time and energy, and they'll do the same for you.
To wrap up, don't be a dick. Make friends. Broaden your communities you belong to, get your name into as many different social medias as you can, but don't spam. And wait. These things take time.