How to better understand and do a good job?

1. Before using notebooks and the like, the subtotals are below, but later found that they are not very useful?Why does this seem useful to me?

2. How to understand other people's words?
It is best to find someone to confirm the code from time to time to prevent it from going astray.
When discussing code, exchanging technical opinions and the like.

I feel that this system does not split the corresponding system architecture diagram, design diagram, flow chart, etc.
It is just imitated.And I don't have a deep understanding and understanding of the imitated system, so I used more technology to realize it.Perhaps it is the disadvantage of iterative changes.

3. Just repeat it and make a record?Basically it's OK.
Achieving detail and accuracy.

4.Result to be achieved: Process line, Testability, Consequentiality.