Brutal I know, and don't take me as generalizing the community as a whole, just a very large portion of it. Ghosts expose players to their cognitive flaws. This game forces you to take a little more care in actions but I'm finding that most players aren't getting this. They play stupid and expect great results. Black Ops II conditioned players who lack the capacity to fully think through their actions and analyze the pros and cons of each possible decision. You'll get burned in Ghosts with careless thought.
The key to Ghosts in being attentive to that which is around you and putting yourself in a position that benefits you and your teammates in the best possible situation to win. Unlike Black Ops II one player could easily carry a team. The maps were small allowing you to be everywhere at once and the rewards were cheap and powerful. Not in Ghosts, if you start getting a head of yourself and create "tunnel vision" you'll lose, badly. Overconfidence will cause you suffering and more over will put your team in a bad way. You'll dig your team a hole and if you can't hold your own then your team will have a hard time picking up your slack.
Observational skills: It's simple really, look. That's it. Use your eyes and examine the area in front and around you before stepping out in the open and get lit up. I love standing next to someone and they just run right past as if to say, "hey look at me, I'm a free kill". Funny thing is, this same person will call you a camper even though it's very obvious that it's their fault.
Situational awareness: In MW3 I really pushed this skill. It's quite possibly the most important skill in video games period. Knowing what's going on around you without being directly told. A good example of this is what I'm going to start calling meta-combat. It's being able to analyze where you're teammates are and generating an idea of where the enemy might be. If you team is merging on on area of the map then you can use that pattern to triangulate the position of the enemy and then execute a flank. This is thinking beyond (meta) the current combat situation to come up with successful plan of attack. Here's a fun fact; most matches that you'll play both sides will try to shrink the map into a small combat area. This happens on even smaller maps like Nuketown. If you have good situational awareness and can adequately use meta-combat skills you can then use the whole map to make the game easier.
Personal space: This isn't a skill so much as a tendency, but I've found personal space issues becoming a huge problem. Ghosts has some very big maps yet teammates want to be right up your ass and draw more attention to your position than necessary. Especially when the shoot like Elmer Fudd at thin air with an unsuppressed weapons. I hate bumping off of people as I try to move around the match, I always end up getting killed because of this.
Playing the whole map: This kind of builds off of situational awareness, but another thing I notice is that teammates will always look where you're looking. I welcome those who want to camp or snipe with me, but why do they always find it necessary to look at the exact same target as me. I understand that sometimes you get bored staring at emptiness, but when I move don't follow me. Ghosts defense against camping is providing half a dozen ways to get to ever position on the map. So don't make it harder on us by guarding the same vantage point as me, there are always just opportunistic windows or doors to look out of.
Know your weakness: This is more of an egotistical problem than anything. Every CoD player thinks they're the best CoD player. Obviously this is a problem when it comes to making yourself a better player and trying to make your weaknesses strengths. I know what my weaknesses are; multi-tasking, movement speed, weapon handling, and putting myself against overwhelming odds. As a player who has camping tendencies I know what I'm most vulnerable too and because I know this I can take mitigations to limit my vulnerability to these weaknesses. If you're not willing to admit or properly recognize your weaknesses then how the hell are you going to be a better player?