wait till the branches are about 4 inches long, so you can have at least one inch in your cloning medium. i use peat pellets, they come with domes but i use a translucent rubbermaid storage box, a relatively small one thats about a foot in length, 8 inches in width, and about 6" high. a good way to practice cloning is to clone other plants if you have them. i grow marigolds, they're relatively easy to clone and they're good for practice. you should use rockwool, perlite, peatmoss, or ive even seen some people do it with sponges. anything absorbent that still lets in air will pretty much do it. then soak them in a low pH water for a few minutes. some do require this, other do not. after the soils wet, take a cutting where the branch meets the main stem, try to take a 45 degree cut so the branch is more exposed. after this, you should soak the cutting in 6.4-6.7 water for a minute, soak the whole thing for a second then i let the bottom of the branch sit in the water for a minute. now, get root hormone, either gel or powder, and dip the end of the stem in hormone. then put the stem in the medium, if you need to poke a hole in the medium before putting it in hormone.
after shes in the medium, she needs high humidity for about 5-6 days with low light, i use shop lights or cfls for this. also make sure the box stays about 70-80 degrees, not saying this is the limit but id suggest it for optimal rooting. also, id use 24/0 for clones but you can take clones outside as well, i do it in the shadow under a table but it works out fine since the temps here are always pretty high.
watch very close for mold and try to make sure the leafs arent touching the walls, this can cause mold damage as well. keep the dome very humid, but you may only need to spray them only once if the box is humid enough. after about 6-7, pop the dome and let some air get in, and leave it cracked open. the next day, remove the hood and let them run under some more light or put them closer to the lights, a little bit of air flow would be good for them as well. i wouldnt foliar feed since you want it to harden off and rely off the roots for energy. if you plant outdoors, leave her in the shadows for a day then put her out for an hour or so the next day and see how she reacts after a few minutes, if she looks droopy you may have to put her in the shadows again.