My arab trainer has me run my reins through the rings of the bit and snap them onto the center ring on the martingale, so when you pull back it tells the horse to lower its nose. I know alot of people don't like this method, adn it's not collection by any means, but eventually they learn to keep their nose in even when its off. You'll have to work up their neck muscles, so its good to release them once in a while.
This post was general, if you want more info message me and I can even send pictures :)
Every great dream begins with a dreamer. Always remember, you have within you the strength, the patience, and the passion to reach for the stars to change the world. ~Harriet Tubman