I don't have much advice to offer on publishing except of the 'don't do what I did' variety. Since I've done quite a lot, I thought I might start recording some of the mistakes I've made and the lessons I've learned.
Lesson one is about ellipses, em–dashes and spacing. There are many different style guides all offering differing opinions on whether an ellipse should have a space before and after. It's important to remember that these guides were written in the days when type was actually set – either digitally or in the form of shaped lumps of metal. With an ebook, there is no set sentence length. The number of words (and characters) will depend upon the device, and the font-type and size chosen by the reader. Hence, if you put a space before an ellipse, the ellipse could carry on to the next line. Personally I don't like this. The ellipse is a way of showing a sentence trailing to off etc, so you need it attached to the preceding word.
And on a similar note. I've just realised (browsing through one of the books) that it doesn't matter whether or not there's a space before an Em dash. If there are too many characters it will be carried over onto the next line. I've no solution to this, since it's not as if you can stop using them, but it is something to be aware of.
So, be mindful of spaces before ellipses within ebooks, and Em dashes. Lesson over.