Probably the biggest thing that I've found makes estimation harder when I lack a clear idea of the goals of the project, what the different pieces are and how t

Probably the biggest thing that I've found makes estimation harder when I lack a clear idea of the goals of the project, what the different pieces are and how they interconnect, or how to start on the first step. This sort of barrier was really hard to overcome as a junior engineer because I found it hard to persuade people that "I don't know" or "I don't know what I'm doing with this" was an honest reflection of reality rather than impostor syndrome. One trick I've found is to work in a company with respected Test Engineers. If you tell them "I could really use an introduction to the different pieces here", rather than saying that you should stop "trying to understand the universe", they are often happy to show you documents like a risk list and other diagrams useful for getting a mental model of a project. If you find TDD useful for getting started and getting into a good cadence with a project, they often have great ideas for how to make a project more testable. They are good people to have backing you up if you're pushing back on other forms of estimate nonsense.