I recently built a tower/obelisk type structure by supporting my character's self on a single stack of blocks, building this scaffolding stack underneath myself as I went up and breaking it down from the top after I was done. This seemed like an incredibly risky and failure-prone strategy, and I would not want to attempt it again for concerns of falling. What are some strategies to build a tower or spire structure of arbitrary height from primarily within the safety of inside the tower itself? Preferably, this should not require a full separate scaffolding structure, but this should allow me to occasionally go outside on scaffolding of some sort and decorate the outer surface. Any suggestions or best practices around this? Thanks in advance.
Dig a trench around the base of the tower two or three blocks deep and two or three blocks wide on each side, and fill it with water. If you fall off (or jump off when you're done) you can safely land in the water.
If you carry a bucket of water with you, you can use it do float down and then swim back up to the top if you need to run off temporarily. The bucket is reusable and the 'ladder' it makes disappears instantly!
Build in iterative stages, a floor at a time, with a sort of spiral staircase structure inside. Every new ceiling becomes a new floor, and quickly getting to the top would be a fairly simple task of running in circles. While you're building, every floor or two, build a balcony that extends all the way around the tower. From each balcony, you should be able to decorate the outer walls fairly easily. Torches that could be hidden on the balconies would both prevent mobs from spawning as well as light up the tower at night.