What attributes do you think make a great cover? Should it contain action? A single character? Should there be a villain or at least an implication of the threat the hero is facing? I'm kind of partial to this one below. Share your favorite piece of cover art and tell us why you like it and why it would make you pick up that book every time!

My brother hates it when comic covers dont look like the interior. I prefer a damn good rendering and I like when the cover is the first page too.
Really great topic! I think a cover needs to be dramatic from the get go. You can make it dramatic from the composition, lighting, color work, etc; everything working together to set the mood for the book itself. It also needs to tell a story within itself, you know, putting the reader imagination at work, asking questions of what's might be going on. It can be super busy as long as you have a good focal point on it, if not is just pure noise and you might end up getting lost with it. That's my two cents.
Yeah, I think most folks feel the same way, RC! And covers don't get more ICONIC than this one! For folks that experienced this book on the racks in real time, it must have been such a thrill!
In my opinion, the covers that really stand out to me are the ones that either highlight an important and pivotal part of the story, or shows some sort of threat to the heroes. The villain doesn't have to be shown necessarily, but so long as there is an inferred villain, that adds to the intrigue.
Looking at this cover, you don't see the villain (or villains), but you can see that the heroes are ready to put up a fight and you can also see a bit of fear. That conveys the importance of what is going to occur in this issue and it draws the reader to it. The most important part of the cover is the intrigue that it awakens in the reader. If there is no intrigue, then it would most likely fail as a cover.
Each book and every reader is different though, so if something works well for a specific audience, then I would say to go with what has been shown to work best.
For me, a great comic book cover is one that can mesmerize me in teasing me on what the book may be about. A cover can also be the selling point of where this book is going to take me. A mixture of fantastic art and beautiful colors on display at the very beginning for my eyes to indulge in is ❤.
I'm also a sucker for tremendous team up covers. Here's one from a long time ago. I remember buying this from my LCS when I was a kid.
Death's Head II Vol. 2 #1. Few covers have ever been made that are this cool. You have to fold out the cover to get the full picture.
So, I'd like to share this cover of the very first Punisher comic I ever bought. I was 12 years old and saw this on a convenience store spinner rack. Being an 80's kid and already well steeped in action movies galore, this immediately caught my attention. I had no clue who or what The Punisher was, I was more into Spider-Man and Batman at the time, but the cover to this comic made spending my $1.00 on this a priority.
All of that being said, let's check off some boxes, shall we?
Action? I'd say yes! We're in the middle of a very tense scenario that's only going to escalate! Seeing this made me pick it up to see what happened next.
Single character? Not in this case. In my opinion, if the cover art is eye catching (as it is with Red Koi), even if a reader is unfamiliar with the character on the cover, they might say "Looks cool. I'll grab it!". But, if its, let's say Spider-Man, and he's swinging around without anything else going on, that probably won't get me to think its a must buy.
Villain and/or threat? Absolutely in this instance. If I see a character that is facing the odds against evil, I'm going to think that what's inside must be more of that! We all know that there is a story inside the comic book, but if the cover helps tell to the story and give a glimpse of what they might be in for, that'll likely get a potential reader to get invested in the story even before they open the book to read it.
After buying this book I instantly became a Punisher fan. It was like watching a new Rambo or Commando or Death Wish every single month. I should note, the topic of this particular Punisher issue dealt with child pornography, which in retrospect was some HEAVY SHIT for a 12 year old. Luckily however, the majority of stories to follow were a bit less intense and serious, more akin to standard action fare.
I hope this helps to answer your question!
I don't know if I've thought of it like that consciously. I think the main thing for me in compositional clarity, something visually striking. I love that Red Koi cover, but I also like team action jumps. I do not want to see "the big reveal" on the cover. I want some mystery. I do not like the "conceptual" overly simplistic covers. Whether it's the main artist drawing the cover or not, I do want it to look different from the interior pages some way.
I'm partial to the idea that the cover is the first page to the story, or sell a dramatic moment in the story- that might come from the comics I read as a kid though, my mother's and uncles' comics were still (mostly) in tact under my grandparent's stairs, tucked behind the toys and board games. Pin up covers can be fun too, but don't really sell me on reading the story if you follow my thinking.
70's Batman covers are sort of my jam.