Plan at least two to three inches of batter per foot of wall height. Greater tilt-back will help compensate for irregular stones and will provide pockets into which material may be planted. Stone chips will help firm uneven stones while you are laying the wall. Another useful item will be a chipping hammer to settle rocks or clip uneven lumps. Lay all stones horizontally with the straightest edge toward the slope.
Bridge joints on each successive layer.
Do not allow long vertical joints. Use a sledge hammer to divide rocks too large to fit into the wall. Steps may be set without the use of concrete. They will be more solid though if the larger stepping stones are set in a bed of mortar. This will make a solid footing without an appearance of the concrete itself.