Heres my system..
-2 or 3 nodes down from the top of the stems canopy, cut at the next node set down (leaving those fan leaves and node sites)and put the cutting into a bowl of water cut side down. Now make a new cut (45* angle cut) with the stem submerged in the water where you cut it (this blocks up the stem with water so air doesn't get inside of it / air pockets are bad).
-After letting the cutting sit in the water for a minute or 2 and suck up a little water dip it into your rooting gel/powder (dont be shy here, get it all over the stem) (I like to coat tail the cutting at the bottom of the 45* cut. This promotes more root growth instead of a tap root shooting down.
-Use cloning cubes like these guys all said. It will greatly increase your success rate. Plant cutting about half way through the cube you use.
-Most clones will take an upward of 2 weeks or more to show roots. Keep them in a clone tent where they'll stay warm and moist. Spray them a couple times a day and let them get fresh air in the tent. (I add tiny amounts of nutes to foliar feed while spraying clones....Tiny amounts!!)
-When clones show there first root or 2 coming out the bottom of the cube I like to cut it.. Just like topping your plant this will promote a more even root base. This is about when there ready for soil and hardening.
I also like to keep my clones in 20+ hours of light per cycle.