Small concrete pier foundations – how do you normally form and level them?

[PileLabProject]

I'm looking at different ways of making small cast-in-place concrete piers for things like small buildings, decks and similar structures.

I'm interested in the practical side rather than structural calculations: how do you normally form the pier, keep the form in position and get the top to the correct level before and during the pour?

What part of the process tends to be the most awkward or time-consuming?

I'm working on an idea around this problem, but before showing it I'd like to understand how people actually deal with it on site.