Wendy asked in tree mail for a little more detail. I thought I would put it here for others to reference or comment on.
Here's a step by step of what I might do with coleus.
These coleus are getting big. Im going to cut a few stems just above about the third branch from the top.
Here are my cut parts. I could have done them even shorter, just the top nodes. I probably wouldn't make them much bigger. Too big is too much work on new roots.
Now I take off the bottom leaf and tiny side branch, exposing a node, the bump on the stem where the leaf was. Nodes are good for making new roots on cuttings, but with coleus they may root right off the stem. I also usually chop the end off all the leaves. That makes it easy for me to see later on which leaves are new since my cutting. And it means less leaf surface for the cutting to support.
Clear cups are nice because you can see when roots form. I put very loose and very damp potting mix in the cups and push the stem down until the bottom leaf and branch are snug into the soil. Lightly press soil around stem.
I would trickle a little water in to make sure it's good and moist. Then since it is very nice out right now, humid, not too hot or cold, I just put the cups in full shade.
Most likely you'll have rooted cuttings in a few weeks. They will start to grow new leaves at the top and the side branches will grow.
