>>9518962
Releasing content that actually shows their work. I know original work takes a lot of time to produce and perfect, but covers, clips of practice, etc. One of my biggest pet peeves is groups that primarily post "fluff" content (selfies, happy-birthday posts, art of the members, "fun facts" about the members) instead of content that shows their skills. It's a different case for idols who are already well-known and beloved, but for amateurs it should be no more than 50% fluff content, because as audience we don't know/like you well enough to give a shit what your favorite animal is or whatever.
Personal appearance. You should at least try to look like an idol in content you post to your page. Know how to dress in cute clothes for your body type, make sure your makeup and hair looks nice, and for god's sake make sure you fix the levels and brightness/contrast before posting. Bangs are always a plus. Idols are supposed to be mostly-average people with a bit more sparkle and cuteness, but a lot of net-idol groups just think average is good enough. I'm sick of seeing "idols" in ponytails and t-shirts with no makeup.
Improvement. I'll forgive a starting group for not being in sync, not having great dance or singing skills, or an awkward stage presence. Part of what makes an idol an idol is watching them grow to something extraordinary. As long as they are doing something concrete to improve themselves, it's fine IMO. Especially for an amateur or self-produced group, I don't expect the skills of professional idols. But they still have to work on improving themselves, and they should be energetic and smiling every step of the way.