From A Book To A Movie

Well, the bad news--they find you.
The good news--here's how:

So the first thing you must be honest about is the appeal of your book as a movie. Sites like The-Numbers have a service where they rate the projected profitability of your book as a movie project.

You have to write a good book, have some buzz going so your book makes it to some bestseller list, (mine was in the top ten for teen horror on Amazon for over three and a half months), then have a movie producer read it, like it, and want it as a project. The next thing they will do is hire a company (like The-Numbers) to see if it meets certain criteria to be profitable.

Okay, let's say you have some producers interested in your book, what's next?
They offer you an option/purchase agreement. Here is one I found online so you can see what one might look like, or not. Cypress Films Book Option Mine looks nothing like this one! My contract is twenty pages long, but they don't have to be.
If a movie contract could be called typical, here is a starting point of what an agent would demand on the front end.
Approximately fifteen thousand dollars up-front for the option to tie it up for one year, (unless your books are well known and then this could be in the hundreds of thousand dollars range). For the exercise of the purchase agreement to go through, approximately 2.5%-5% of the bonded production amount, payable on bonding date or first filming date. 2.5% of the backend. (Ticket sales.)
Does this resemble the contract I'm signing? No. My book series is not well-known, I'm not well-known, and therefore I have very little bargaining power. Do some aspects resemble this model? Yes and no. I'm asking for as much as I think I can get, which is what you should do too. The producers will have a breaking point of what they will and won't do and so should you.
You want to make sure you keep all-rights to your books and characters so you can keep writing and selling books based on them. Make sure you discuss who owns gaming and merchandising rights.
If you're not happy with the agreement, don't sign it.

I recommend you hire an entertainment lawyer like I did. The following is not legal advice, but merely my opinions.

Caps are normal (again you can try and get them to remove caps, the more successful you are, the more likely you can get them to bow to your will), so they can figure financing. Percentage on backend is all well and good, but usually small and depends on the movie being successful. Your best bet is to get as much up front money as you can (just like an advance on a book project) as it may be the only money you see.
Keep your copyright and all rights to your characters for future books you may write. You can give/sell the production company a license to merchandise off your characters.
Producers, if they are small, may buy your option and then try to resell it to a larger production company.
Large production companies may budget a couple of million a year to buy twenty books in a genre and then only make one of them into a movie, but since they own the option for a period of time, they cut down on the movie's competition, and if it's successful, they can choose another they bought and then produce that one.
Going with a mid-sized company, your book is their next project. They can't afford to tie up too much money in options, but they have enough money/investors to go forward.
Options last for one year. They pay you for tying up your book at this point. If they exercise the option (means: plan to move ahead with the movie), they pay you again. You can request backend, but they can say no.
These are just the basics; you should hire an entertainment lawyer who has represented authors on book to movie deals. A lawyer will most likely charge you a per hour fee to review the contract, but you can write into the contract for the production company to reimburse you your attorney fees.
Specify an on screen credit, because the only thing cooler than seeing your name on a book cover, is seeing it on the big screen.