As has been stated in other comments, the type of game you are looking at dictates what needs to be learned to get better.

Shooters require a different skillset than say an RTS, which is quite different from a turnbased Strategygame, which is completely different to a mechanical skillbased game like tetris, which is different to a card game like magic or Hearthstone.

If you are looking to get better at videogames in general, just play different videogames and try to identify what skillsets are required in them.

If you have a specific one in mind, or a genre, more detailed advice could be given.