I shoot a single action with about the same technique I use on an M1911 -- that is, a modified Weaver grip. One thing that may help is oversized grips -- many revolvers will rap your middle finger in recoil, and that doesn't help accuracy at all. You can get a large, rubber grip to correct that for a few bucks.
Another thing I do is use a cross-X rest. I take a piece of leather, about 3X8 inches fold it lenghtwise, and sew along the edges (something like a pillow.) The seams don't meet in the middle -- there is about a 2-inch gap. Insert two dowels, one from each direction, and spread. The result is a pistol rest with the leather holding the dowels together at the head and forming a pistol rest. Use this from the sitting position with a solid backrest -- a tree is good.
Use ammunition of known quality at first -- many Rugers require opening up the throats to shoot accurately. If you get good accuracy from your ammo, while using the cross-X rest, you know that inaccuracy from the unsupported position is due to the shooter.