Excellent comment, I couldn't agree more! Just two things to add: For general language skills, find authors who have good style and read as much of their work

Excellent comment, I couldn't agree more! Just two things to add: For general language skills, find authors who have good style and read as much of their work as you can. They might be well-known book authors (I personally enjoy CS Lewis and EO Wilson, amongst others) or a newspaper with a high standard of penmanship (to German readers I recommend Die Zeit, I'm not sure what an English equivalent would be). You should read a bit of everything, but emphasize the type of writing that you are going to be doing yourself. For example, scientific papers require a very different style of writing to, say, newspaper essays. You need to be thoroughly acquainted with the type that is relevant to you. (Finding your voice comes later, first you need to master the basics.)