I like having a character or two so that I can see the style and the quality of the comic.
I prefer comics that have a more western style over an anime style...And a prefer a more cartoony style over a more realistic comic book style.
I tend to not click on comics with an image that looks like a quick sketch drawing or a pencil sketch or anything which is over simplified (like just a smiley face or a solid color and some text)
In general, I noticed people tend to use blues, purple, reds (pinks) colors. And I notice people are less likely to use yellow-greens and oranges, plus yellows in general is less common. Colors can do a lot to set the tone of a series. A romance may use red or pinks, a drama may use blues, a comedy may use oranges. Red can also be used in horror. Green could help show "fresh green nature" but it could also be "gross and rotten". You can research colors and meanings if you feel like this is very important (don't solely take my word for it)