Regardless of the specific method you choose to improve your writing, you should aim to set clearly defined goals and expectations. Having goals that work in your favor make a gargantuan task like improving your writing much easier to see consistent improvement. The goals that you set should be specific enough that you can clearly identify the aspect of your writing that you're trying to improve. To do that, it helps to have a clear target for what you're shooting for; specific examples and expert writing from the field you're interested in are perfect for this. The other part is about keeping your expectation tempered. It takes a long time and a great amount of effort at any craft writing is definitely no exception. Its important that when you set goals, you've got to go for something that just barely out of your reach. Go to far, you likely won't learn anything, you'll find yourself frustrated and disillusioned. Practice won't make you perfect. Practice will make you better. Its all we can strive for