How can I improve my English for writing?

[thought]

Practice writing in English, and read more in English. It's okay if it is hard: muddle through and you'll get better with those detailed descriptions.

Dino, since English is in this case a proper noun, it should be capitalized. No comma is needed after "improve it" because what follows is a simple dependent clause ("so" by itself signals an independent clause, but "so that" signals a dependent clause). While "to begin with" is not a colloquial phrase, it is a gerundive in the position of the ablative: it's grammatically correct and can be left as is (a more natural phrase, though, would be "from the start"). You did, at least, get the final suggestion right. You're welcome, by the way.

Tippy, as you can see, even English speakers do not always have the best grasp of the English language. It looks like you have a good grasp of most the language, and just need practice to learn the quirks.