Depending on the cork (I use both real bark and veneered tile) I usually first drill a hole, a bit larger than the base of the brom, and then wrap a small amount of sphagnum around the base of the brom and set it in the hole. Sometimes I'll glue them in. Some bark will even have a perfect crevasse to stick the base into without drilling.
I will then either drill a couple holes, slightly smaller in diameter than the toothpicks, or, if I can, just push in the toothpicks in on each side of the brom at an angle so that, once inserted, they form an upright 'X', angled away from the bark on the top, and partway up from the inserted base. The plant is supported in the upper crotch of the 'X'.
I may add a solo toothpick higher up, stuck into the bark at a severe angle, pinning a leaf or upper stem as well, to minimize movement while the plant roots. Sometimes I'll pin it right through the leaf.
I always take the points off the exposed end of the picks before inserting.