I guess i am one of those people who can find something i like about most images. It may only be the colours, or the lighting, but ill comment on that. If someone has gone to the trouble to put their best effort into a work, and proudly put it up for display, then who am i to concentrate on the negative, rather than the positive sides of it? If i dont like something about the piece, i just dont mention it. It may be that the artist likes it the way it is, and even though i may not, thats only my opinion.
I dont mind offering suggestions or an opinion about change, but unless the artist has stated that theyre not satisfied with the image & asked for improvements, then i dont usually feel comfortable doing that ( again, this is just me personally )
Rankings i rarely do unless a fractal really 'speaks' to me, and i havent used rankings on my own work for ages. I would rather see someone comment in a little depth about why or why not they dont like one of my fractals, rather than say 'wonderful' and hit the excellent button cos they feel like they have to.
I like getting comments about changes and i also like people offering suggestions or improvements ( in a constructive way, which is the key ) The only times i have really recieved those kinds of comments however, are when i have asked for them.
On my own work, dont be afraid to offer a suggestive change if you feel like you want to. Seeing our art through other peoples eyes, and trying out others opinions can only help the learning curve.

As for cliques, i cant comment on that, im really a ghost around here lately lol.
I dont seem to find the time to be able to look through the galleries lately, which is a shame