ok some of you girls are actually clueless about all this so here are the things that I believe are the best for growth:
#1 collabs, collabs put you on the map, they tell people that you exist and are a good way to get followers, if you aren't decently big, you have to organise the colab yourself and invite bigger vtubers
#2 longer streams: the longer you stream, the more the chances of getting raided you have, also, making tons of short streams doesn't help because chances are people won't even have time to realise you're live
#3 twitter presence: post art, post clips, post whatever, it helps people that don't know about get to know that you exist
#4 short clips: don't make your clips too big, don't make compilations, only your already existing fans will watch those, make them short and impactful
the content you do also matters, some games are straight up a debuff, new people will join if you're playing a popular game, I've noticed that older retro games attracts lots of oji sans to see a cute girl playing their childhood game. playing games that nobody knows is usually a big debuff. you have to find something that is popular but not TOO popular, people are tired of watching girls playing doom for the billionth time.
ASMR brings in a lot of people but they usually don't stay. karaoke doesn't seem to do much but idol streams like 3D dancing helps a bit. drawing only brings people if you're good at yappin
finally, if you are going to stream, MAKE SURE EVERYONE EVERYWHERE KNOWS, a lot of people just start stream without telling, on youtube subscribers get notifications of phone but not on twitch.
speaking of which, if you can dual stream, then do it, you lose nothing by doing it.