A chess teaching website named Chessfox has this model of chess skill, which shows the parts of chess skill.
Understanding of opening principals, knowing the characteristics of major openings and deciding your own opening repertoire, are all important traits of a chess player. At upper levels. there is the need of deeper opening research; you’re trying to gain an advantage in the opening especially with the white pieces.
Planning is also an important part of chess skill. It includes for example knowing types of positions, using lines and diagonals effectively, using strong and weak squares, knowing how to play in certain pawn structures and overall deciding, what you want to accomplish in your next moves.
This skill is about answering for example, which player has the safer king, which player has advantage in development/more active position, and which player controls the center better. With these and other questions you can answer the question: which player has the better position?
Some say, that endgame technique is the one most important part of chess skill. Endgame is part of the game, in which there are only a few pieces left. It’s like the las minutes of an ice hockey game: the game is decided there and a small error can destroy an otherwise long and great game.
Endgame skill includes knowledge of basic endgames, principals of endgame (like opposition), king activity, pushing pawns forward to promote them to a queen and mating the king with only a few pieces.
Visualization means seeing the later moves in your head. It’s very related to calculation.
In chess, you’ve got to be able to calculate a few moves forward. Over hyping this skill however is one reason, why chess is thought of being hard and off-putting. Chess skill isn’t only about this skill. It’s an important part of chess skill, but you get better at it, when you keep playing chess.
Tactics means planning and executing small operations. Chess has many tactical motifs, like forks, pins and double-checks. It’s good to know these motifs. Tactics usually decide the game in a final matter.
All these skills form the chess skill together. Players have got to aim for comprehensive chess skill, not to study only one of the part-skills. Of course. some players are better at some skills, but they should better their weaker skills then.
What do you think about Chessfox’s model? Should something be added or deleted from it? In my opinion, the model is pretty good, but you could maybe add knowing yourself and knowledge of playstyles to it.