Here are some heuristics I use in life and work:

• Play to your strengths; being balanced sounds nice but ends up being really unproductive/unpleasant.
• Spend time on the things you like, as time and practice pile up you will end up skilled in those domains.
• Go for the things that are of interest to you, not for the trendy ones.
• Time spent automating tasks is usually time well spent.
• Taking a break to gather knowledge on something vaguely connected to the thing you are doing is never time lost.
• When you have been procrastinating something for most of the day, declare that you will not do it today and that it is okay; it will free your mind to do other things instead of leaving you stuck.
• Try and do one, single and quantifiable, thing a day. With time, they pile up, and you end up doing a lot of things.
• The mind is good at criticizing something but bad at doing something from scratch: instead of trying to produce perfection, do a rough draft and then improve on it incrementally.
• Also, be nice, kind, and nonjudgmental to people.