Principles of time management:

1. Concentration. Non-interrupted work on the problem increases efficiency thanks to accumulated information about the problem in the brain cache (temporary) memory. Interruption makes it difficult to come back to the problem solution next time.
2. Simultaneously doing "must" and "want". There are a lot of problems we meet during our life. They result in "must" tasks. We should do them anyway. If we have long term illness, we must attend a doctor. Otherwise we could die. Every morning we must go to the toilet. Otherwise... you better don't think what could happen.. I "want" to write a code. However I "must" sig in the toilet for a long time e. g. because I did eat something bad. The obvious solution is to sit in the toilet with the laptop.
3. Don't allow "must" tasks to take a control over my life. If I work the full time job that I don't like, I should spend there only hours necessary to survive (pay rent and get groceries). Not more. The ideal way is to get "must" work simultaneously committing "want" tasks. E. g. night security guard who is not busy enough with his main duties.
4. To be continued