Hi! That's wonderful! I can't wait to read them.
And it all depends, I've read a few books on "how to start books" "avoiding cliches" and "introducing characters". They provide general tips but I think most of the time, you just have to experiment.
As for the writing decisions, I like to write as much as I can without overloading myself. I always have 'maps' so I know what's meant to occur next but I don't usually finish a whole book and slowly publish it, mostly since you can always get a new idea and merge it into your story, if it's appropriate with the rest of the story and it's not too late to add such part.