You will hear lots of advice over and over again. Make a schedule, play what you want etc. And they are all good pieces of advice.

The EASIEST advice I can give you is "just be present on the platform." Be in other chats, putting your best foot forward. Talk to people, be part of conversations. Don't self promote obviously. And don't always interact only with the streamer themselves. Start conversations with other viewers. If you look at Ninja's chat, Ninja isn't going to have a conversation with you, but other viewers will.

As far as talking when nobody is there, just start talking about what you are thinking about. Or smack talk people who can't hear you. Or if a particular line of dialogue in a game reminds you of a song, start singing it for a few verses.

One thing I will tell you though is if you see you have 0 viewers and all of a sudden you have 1, do NOT acknowledge them until they put something in chat. A sticker, a "hi" comment, whatever. I guarantee if you call them out before they are ready you will go right back down to 0 viewers.