Unfortunately there is not much else to preach about shooting from an elevated stand or for that matter shooting on a steep uphill angle. Your form should be the same as if on level ground. I have seen some guys throw back there hips to set the angle but in the end it just takes practice.
Some guys will draw and bend at the waist. For me I bend that the waist then draw but I tend to swing draw and this method works better for me.
Jimmy Blackmon has a Youtube video on shooting from a stand that may help.