Update FANBOX at your own pace, but challenge yourself to continue to create new and interesting content that will engage people who aren't yet your supporters, and people outside your group of fans.If you stay active, this will also engage your current supporters.
It's important to increase your number of followers on pixiv, X, YouTube, and other social media, to boost the visibility of your brand.Your number of FANBOX supporters will never be higher than your number of followers on social media.
Expect that on average, about 1% of your social media followers will become your FANBOX supporters.Aim for that 1% as your first goal.If you don't get that many supporters, it's likely not because of the quality of your content, but because you haven't done enough promotion.