>>5781466remember concept art not about art, design comes first, many forget this and worry about rendering/polish too much. apply composition fundies to individual subjects, ie. prop/vehicle. basic fundamentals are important, thats how you communicate design.
skillful huntsman is still a good example of what 'concept art' is, and it is not illustration. closer to graphic design than illustration. if u want to be a concept artist, study design foremost from real life (form/function/organization), from peers (artstation, etc.), and blend personal interests and taste into that. prioritize sketching and design assignments with lots of iteration, only true way to 'get good' is to churn thru bad designs.