Which is the best way to improve your game?

How do you  improve your game?

Is better to play a lot of matches or study first and then practise.

And if you study, How do you study?

Do you focus on a position and you calculate many variations?

What is necessary to improve the game?

As a beginner - tons of tactical & checkmate puzzles & playing games against stronger players.

As an intermediate - tons of tactical puzzles & playing games against stronger players & also studying endgames, openings & master games.

Beyond - if/when I get there I'll report back.