With the stem plants you can just cut any where really and replant. Though there are little bumps, usually where leaves come out of (It looks like it breaks the plants off in segments) is where you want to cut under. This is because that is where the roots come from.
With the tiger lotus and sword plant you would just cut close to the bulb (lotus) and rosette/crown (sword). The crown is where all the leaves will come out from, the closer the better.
15 Gallon NPT
1g no tech bowl in the making