45° angle cut with a clean razor blade, new is not clean it is oily.
Cut new growth making sure to leave 3 nodes on the plant you cut from, old woody hollow growth is harder to get to root. They will root in just water if you make a clean cut without smashing the membrane.
This.
Also on a side note there's loads of tutorials here on Riu.
Also
https://www.rollitup.org/t/easy-diy-20-bubble-cloner-a-picture-how-to.835810/ If you wanna clone easy mode.
There's 100s of videos on youtube.
A few helpful hints. Along with leaving a few nodes at the top. When you take a cutting I've found better rooting success with having a node or 2 at the bottom as well. Cut off all the leaves etc. Leave the stem submerged in your cloner. Or if you want to go old school have it buried in your medium.
I actually have a plant I want to keep around. It won't root for squat in a bubbler or just leaving it in water. I said screw it and gave the old cloning in dirt method a try. Took 8 cuts from the only one to root from bubbler. Built a few Diy pots out of clear solo cups (to see if there's root growth) Tossed some promix in them. Used more clear cups as humidity domes. In 5-7 days they all could survive without the tops on them. RH in that room is a good 65-70. Temps around 65. In 2-3 weeks I'll be damned in every single one didn't root. Not a single one wilted. They didn't turn yellow. Nothing. They were totally content in soil and cheap rooting powder I got from a lawn and garden center for 5$. Some plants are just fickle about rooting. This is one of those cases. I didn't even shave the stems or anything. Just left 2 nodes of growth under the soil. Hell I plucked it off with my fingers.
But save yourself a load of frustration. Build a bubble cloner. Or just buy one off the net.