Cloning is fairly simple you have to follow simple rules. Ive done somewhere around 600-800 cuts last year myself.
1) Only select healthy cuts, usually from the top of the plant.
2) Proper environment, you need a warm location, 75-80F, Domes to keep humidity in, and eventually you will have to harden them off by taking off the dome. Use Flo's or CFL. There is an optimum environment for cuts.
3)Proper air/water ratio in your medium or cloner. Rockwool, Vermiculite, Coco. etc.
Too much water causes stem rot and a failed cut. Like rockwool cubes need to be flicked a few times to shake out excess moisture, Coco on the other hand needs to be packed into a propagation cell so the cutting will stand. My aerocloner needs a timer to keep the pump from getting too hot and heating up the solution.
4) Sanitation, start clean, and keep it clean. because of high humidity. You expose yourself to stem rot, PM, etc. If you clone directly to soil consider using a product that has fungicide in it.
5) Use rooting hormones, cannabis usually does not require it. However to increase chances of your cutting taking root find a product that has IBA or NAA in the formula. Hormex for example has different levels of hormone in it for more difficult cuttings. I personally prefer a concentrated product like Dip and Grow. You can control the concentration with dilution. You do not have to spend alot on fancy gels a generic formula found at most garden stores is usually a stronger formula than what you find at a grow shop. You can manipulate natural hormone levels by trimming the top of the cutting, so the plant will focus on root growth.
6) Some cultivars are hard to clone.. SFVOG was hard to clone, GG4 can be troublesome, some like Chemdawg 4, are easy to root. Some like headband do not like clone hormones.
7) Use mild feed formulas when roots show, aggressive rooters will show PK problems, adjust formulas to prevent red stems. A good clone will look green with no off colors in the stems.
Hope this helps