How to more accurately estimate software development time?

Question

Project management

I can’t rely on experience and colleagues (and I don’t have either). From the fact that I will break tasks into subtasks, it will not become clearer how much time it will take

Answer 1

Estimating time comes with experience.
No instruction or utility will help you calculate the time of your creative work for you.
In terms of methodology - Agile with the correct formulation allows you to solve this problem in the long term - when tasks are allocated for each sprint, they are completed, and after the sprint a retro is held, where it turns out how the tasks were completed, and whether it is necessary to
a) increase the estimated time
b) reduce estimated time)
c) it is better to decompose
d) to allocate investment tasks with the definition of time for its solution as a separate task
e) other options, for example, allocating xx% of the buffer time without specifying what task they will go to, refactoring the teams themselves, attracting analysts, and what else is enough imagination.
Thus, if a certain team works for a long time, with each iteration (each sprint), the performance of the team becomes more accurate, the tasks become more understandable.
When moving to a new team - start from the beginning (taking into account experience).
To summarize this verbal flow:
Experience helps. Individual and team.