Anything will do: small pebbles, styrofoam, or, as I use here, a bent can lid.
Step 2: Add potting medium.
The potting medium should drain well. It can be any mixture of potting soil, sand, and perlite. Here I just use straight perlite.
Step 3: Put a large drop of rooting hormone on a clean surface.
I use the bottom of the tin can just because it's easy to dispose of.
Step 4: Cut new growth from parent plant.
These directions are for vines (these images are specifically of a passionflower vine growing near my house), but will work with slight variations for succulents and woody plants.
Step 5: Cut a segment from your cutting.
The prime stock is the section near the tip of the vine. Cut just below the second to last mature leaf node.
Step 6: Remove bottom leaf and any tendrils.
The roots often sprout from the leaf node once submerged in the potting medium. The leaf and tendrils can be discarded.
Step 7: Dip cutting in rooting hormone.
Make sure to coat the sides of the cutting a few centimeters from the bottom as well as the leaf node.
Step 8: Place cutting 1/2 inch deep in potting medium.
Make sure the leaf node is buried.
Step 9: For further cuttings, make sure to take a complete segment.
That is, use a segment between two leaf nodes. Remove the bottom leaf and treat the bottom and leaf node the same as your first cutting. Dip in rooting hormone and plant in the potting medium.
Step 10: Place the pot in a saucer full of water.
The potting medium will suck up the water and moisten the cuttings without washing away the rooting hormone. When the top of the potting medium is moist (or the water level has stayed the same for a while), empty out the water. If the pot sits in water, the soil will be too wet and the cuttings will rot.
Step 11: Cover the cuttings with a plastic bag.
This will keep the cuttings from drying out. You don't want them to be too moist, though, so remove the bag for 15 minutes every day. If you can't, poke some holes in the bag so that air can circulate.