Hi again, Dimitri.
I think these instructions on how to complete your novel will help you move along:
You can also order a free e-book with this one!
The ideas here are great, (I've used them myself) and also include information about publishing and self-publishing (click the link on self-publishing):http://www.wikihow.com/Write-a-Novel
I know that typically, literary agents and/or publishers ask for either the first three chapters or three chapters from the middle of the book, to get an idea of what your story is about, how well you've written it and if it is worth them pursuing it, so honing your first few chapters to get them to be the 'hook' that interests the publisher (and the readers) is a good idea.
Don't let the many ideas swimming around in your head deter you. Consider each one, throw out the ones that you know won't work for your purpose, and pursue those that you feel will yield the best result and fully convey what you want to say. If you can't think of anything at the time, leave it for a while to clear your head and then go back to it. Jot down ideas that may come to you during the day, wherever you are and then see if they will apply to your writing when you get home and try different scenarios to complete your book.
Editing, re-editing, proofreading, etc. is very important, as you may catch something that didn't draw your attention before. This might also want to make you change the order of chapters or add additional story details.
I hope this helped!