Probably the best advice for style is to write the way you talk. The problem is that you can't. Or, rather, you shouldn't. No matter how much we want written words to sound like speech, they are fundamentally different.
Certain techniques of speech simply do not work in print. In speech, you are making things up as you go along, so when you forget to add a subject, or suddenly realize you changed tracks without saying anything about it, you can tack that subject in, as though it was always supposed to be there. In speech, you can make a slip-up, say a wrong word, say something kind of dumb, and you have to either correct yourself or hope nobody realizes it.
Certain techniques of writing do not work in speech. Writing can use tools like hyphenations and dashes, foot notes and headers. We can write in a more visual manner. This is great, seeing as how reading requires looking at it. But, this does add to the difficulty.
There are several techniques that do cross over from writing to speech and back again; that's why the advice is there in the first place. However, there are no hard and fast rules. It is up to your gut and your eyes and ears to know when to write like you talk, when to talk like you write, and whento leave the two separate.
You can do it. So, go and do it now.