well, basically if your plant has 4 or more nodes, you can clone. Its kind of a bitch to clone with smaller cuttings, but you can still do it. If you want to top your plant, and use the top that you cut as a clone, from what i understand those are really good to make clones out of. after you take the 1st top, just wait a week, n you can take two more tops, n then leave the plant for a couple weeks to grow out all bushy. After that its open season man, the bulkier the cutting, the faster and stronger it will take root. N as long as you give your plants enough time to recover, you can keep taking cuttings from them over n over again man.
Good cloning solution to use i would say use Olivias cloning solution, or what i use, plantronics rooting gel. Its awesome, but expensive. Worth it though, thats for damn sure
good luck man!
-K1.