I haven’t found any of these conditions to be necessary, though of course YMMV.
What matters is that you build some concrete thing, for people (not just yourself) to actually use. The details are inconsequential (and will take care of themselves, if you care about building it right) as long as that basic goal structure is in place.
With a time limit, enforced by someone else if you can’t do it yourself. Actual stakes that you care about if you fail are also helpful.
If you can’t do this with a job, do it with a hobby organization (e.g., offer to teach a workshop on the thing you want to build).
I haven’t found any of these conditions to be necessary, though of course YMMV.
What matters is that you build some concrete thing, for people (not just yourself) to actually use. The details are inconsequential (and will take care of themselves, if you care about building it right) as long as that basic goal structure is in place.
(making toys for people is an example that works for me.)