1) Stream because you like it, and think it's fun. No ulterior motives.
2) Be consistent. Even if you have very few viewers. Don't call out lurkers. Let people chill.
3) Be unique, be it gameplay, content, or personality.
4) Get lucky.
It's basically all about those factors. Consistency is important if you wish to grow as a streamer. Remember, Rome wasn't built in one day. Most big streamers streamed for years before blowing up.
You don't need to be a god at games to be a successful streamer. If your "skill" isn't at the level where your content factor could revolve around pure gameplay, then make it about something else. Personality, unique games, comedy etc.