An internode is the place on the stem where the leaf (plus its stem) intersect the main stem. When taking a cutting you must cut it long enough to have at least one trimmed internode under the medium. Try to take a cutting that is at least 3 inches long. I visualize where to cut first. I'll cut the branch about a half inch below the node I plan on being below the surface of the medium (more than one node can be under the medium surface). Once the cut has been made, I trim off all leaves and branches except the top two fan leaves and the growing tip of the branch. This will leave a nice stem for planting.