I want his topline to be prettier and his head down, neck rounded.


How should I hold the reins in order to get him into this position?

What should I do with my legs and how I should I continue to hold the reins so that he stays in the position?

Get an instructor, or get a few lessons from a dressage trainer. you hole the reins no differently than regular riding. you have to collect your horse and get him using his whole body and he has to be flexed in the direction your going. you dont hold the horses head in this position he has to taught to carry himself. but for asking for a head set you sponge the reins. (sqeeze the right rein like your squeezing a sponge once then do this to the left hand and repeat. at first do a firm squeeze but when he drops his head where you want it do really light squeezes and if he pts his head up go back to firm squeezes.) you have to have contact with yoru horses mouth to do this, but. this is no rounding his whole body you have to learn to collect a horse to. a head set is just where he carries his head. but you dont want him to be flat and stretched out. you want them collected. not just there head cranked in. collecting your horse with lower his head and get him using his hind more. pets question and answers,www.5d2d.com
http://en.wikipedia.org/wiki/Collection_ ...
read!! this tells you about collection
http://www.equusite.com/articles/riding/...
this link will tell you how.
But i strongly suggest to get some dressage lessons or get a few lessons with an experienced instructor to help teach you. its hard to do with out being taught correctly.

Get a good dressage trainer, one who has shown above PSG with success. Really. There is SO much confusion about proper dressage, and it isn't something you can understand by watching horses or looking at pictures.

The frame you see the horses in isn't just the head, and it isn't something they have to hold in place. The horse first must accept and seek the contact, but past that it comes from BEHIND-get the horse truly supple and through from behind and the head and neck will fall into place. You cannot pull them into being round, or figet with the mouth until they tuck their nose-Until the head and neck position come as a result of a correcly moving, through hind end, it will always be incorrect and false. It can be false in that the nose is forced in but the horse remains braced against the bit, which is where you see the upside down neck forming. It can be false in that the horse sucks back, away from contact, and just tucks his nose while his hind end falls out behind him. But it can also be false in that the horse accepts the contact but has no elasticity, which is pointed out when a test calls for a stretchy circle.

All you SHOULD have to do is keep steady contact with the reins and leg. But that is rarely the case, which is why you need a competent trainer to evalulate from the ground.

I suggest having a coach help you with this however I will tell you exactly how I've always been taught to get a horse into a frame.
A frame comes from the horse's hind end, many people try to bring a horse's head round THEN ask them to track up with their hind end, this is completely wrong.
First off start at a walk. Ask your horse to walk up using a little bit of leg and seat, simply close your leg around your horse and drive your horse forward using your seat, so that it has lots of impulsion in its step, ensure that the hind foot is landing right where the front foot was (this is called tracking up). With this impulsion you will feel your horse is coming more and more into the bit . Keep nice and soft hands with contact with your horse's mouth and simply keep your outside rein steady and gently squeeze with your inside rein. Squeeze your inside rein with constant and tight squeezes. Each squeeze you should pretend as if you are ringing out a sponge . Once your horse's head has come in and if completely vertical from the ground simply stop squeezing and keep a constant steady contact with your horse's mouth. Never throughout this entire process along your horse to lose its impulsion, if your horse is not tracking up yet it rounds its head you are bringing it into what is called a false frame.
Just remember to do all of this you should be riding you horse with the reins between your pinky and your second last finger with your thumbs on top. You should have a nice bend in your elbow and be sitting up straight with a deep seat. Keep your heels down and ensure you have a straight line from your heels to your hips to your shoulder. Also look ahead and ensure your hands are as soft as possible, this will help prevent your horse from fighting your hands and instead flinging its head up.

go get a trainer FOR SURE.