Ok, first of all....the white thing you see is actually the thin layer where the roots will shoot from. To cut clones, you should cut a stem that is not too thin or thick. it needs to be strong enough to hold itself up but thin enough to allow easy root penetration from inside the stalk.
I cut my clones with scissors.....yes i said SCISSORS lol, and then use an exacto knife to slice a 45 degree angle on the tip. Next, you want to scrape the outer layer off the stem at the tip, where you want roots to come from. Dip it in water, then the clonex, and then directly into your rockwool or soil plug. I've used both, and also just filled a tray with perilite, stuck them in and got roots in 5-7 days.
Check out my threads, grow journals, and pics., There is alot of info in there for you to use.
Next, the relative humidity needs to be around 75-85%, with temps in the 75-80 range. I use a heat mat and thermostat under ALL my trays to control temps inside the dome. The lights are flouro's and i dont mean t5's, i use the regular tube 25 watters for a 4 foot shop light. I use a tall dome, and the light lays right ontop of the dome.
I agree with the others, PATIENCE is #1 RULE in this hobby of ours. Cut,plant, and watch.....ONLY WORK ON PLANTS WHEN THEY NEED IT.
I mist the clones, NOT THE RW, twice a day, and dip the rw cubes or plugs in PH balanced water with a drop or two of superthirve when they show signs of needing water. YOU CAN STILL OVER WATER CLONES (FYI)
Good luck to you, if you have any other questions feel free to ask