Everything depends on what do you want to do in game industry. A job as a concept artist involves both creativity and skills in quick sketching, coloring and gathering inspirations, also photo-bashing is a common practice. Sometimes a company requires to know basics of 3D modelling and rendering and it's a huge plus if company is developing 3D games.
As an ilustrator f. ex. you have to show absolutely the best skills in painting and there is no space for mistakes. It's much harder than simply to make concepts.
As a 2D graphic, you have to know about design, user experience and of course a mix of skills which helps you to make good quality backgrounds, characters, items, concepts, etc.
As a 2D animator is good to know how Unity engine works, how to deal with bones and classic animation.
Each company has their own target.
It's good to play new games and to get closer to developers communities as they often share progress and ask other developers for advice. You can learn even without making your own game but it's good to start at least a small project :)