Think for a moment about the things you’d like to be able to do in Chinese.
Would you like to be able to read a newspaper?
Would you like to be able to understand T.V. shows?
Would you like to be able to speak fluently using well-formed sentences?
Probably you’d like to be able to do all of that and more, unfortunately, there might be a large gap between your current level and the level required to be able to do those things, and so the question you find yourself asking is: how can I improve my Chinese so that I will be able to do X?
Regardless of X, the answer to this is simple.
If you’d like to be able to do X, the best way to learn it is by doing it.
The reason for this is that by doing the thing you want to learn you’ll quickly bump in to problems that are holding you back.
Each bump is something specific that you can work on and improve so that it doesn’t hold you back as much the next time, and each time you fix one of those bumps your ability will improve. Once you’ve fixed many bumps, you’ll find that you have made noticeable improvement.
Which is to say, by practising the things that you want to improve, you’ll find out where any problems and weaknesses are, and once you know that, you can devote time to fixing them.
If you don’t practise the actual thing that you want to learn then you’ll never get a good understanding for the things that are holding you back, and there’s a good chance you’ll be spending your time on things which you think are important, but in reality might not be relevant to whatever it is that you are trying to learn.
Yes, there will always be some degree of crossover with other skills, so the vocabulary and grammar you learn when reading newspapers will help you watching T.V. dramas, and watching T.V. dramas will help you with conversation, and so on, but there is no substitute for actually doing the thing you want to learn in order to learn it.
Therefore, if you’d like to be able to read newspapers, the best thing you can do is start reading newspapers and learning the things that you don’t understand.
If you’d like to be able to watch T.V. shows, the best thing you can do is start watching T.V. shows and learning vocabulary and expressions that you don’t understand, while repeatedly looping sections of audio that you can’t process quickly enough until you reach a point where you can process it quickly enough.
If you’d like to be able to speak fluently using well-formed sentences, the best thing you can do is practise speaking well formed sentences out loud, recording yourself and making corrections, and once you are comfortable with a sentence try dropping it in a conversation with a native speaker and see how it goes.
Initially, you will find it difficult to do things that you are not yet good at, but it will get easier with regular and consistent practice. You’ll also be learning vocabulary and skills that are directly relevant to you at that point in time - unlike say learning from a pre-made deck of flashcards that may or may not contain vocabulary relevant to you and that won’t involve practising the skills you need (unless you are training to become the world flashcard champion).
Doing the thing that you want to be able to do will give you concrete feedback about specific points that are causing you trouble and it gives you something tangible to fix and improve. You just need to do that thing regularly and consistently, and make improvements whenever something causes you to stumble.
Don’t expect to get good at something without practicising that thing, and don’t expect to get good at something without regular, consistent and correct practice over a sustained period of time.
This applies equally well to Chinese as it does to anything else you have a mind to learn.