Cut and propagate the top? How to do it right?

I have not been the best owner but I really want to save this plant and perhaps propagate the top.

I have heard that if i cut the top the plant will create more stems and that if I stick the top in water it will root. Could you please give me tips on how to not fail at this; Where should I cut? Do I cut in an angle? And for the cutting; just put it in water? submerge the whole stem?