I will split my answer in 2 parts: General and Particular (what works for me beside the general).
I have to mention that sometimes I'm a hypocrite as I know what I have to do and I'm still not doing it and paying the price for it.
General:
1. Plan ahead. Know what look you want for your tank and stay on course. Research what you want to put in your tank.
2. Keep it simple.
3. Do not cut corners.
4. Maintenance should not become a chore. Have everything accessible and easy to do.
5. Good reliable equipment.
6. Good lights.
7. Keep your hands out of the water unless you really have to do something. Do not thinker with the system on a daily basis.
8. Water Stability - the most important
9. Changes should be made slowly.
10. Create a schedule (ritual) for maintenance, water changes, feeding, etc. Do not skip it as you try to achieve an equilibrium in your ecosystem.
11. Patience.
12. Have backup equipment.
13. Automation where possible but don't complicate it.
14. Good test kits and calibrate your probes.
15. Dip and quarantine any new coral and fish
16. Quarantine tank ready to go and Frag tank as backup
17. Know your system.
18. Everything you do should be logical, should make sense and be fully understood.
19. Keep a log of what you are doing
20. Enjoy your tank
Particular:
1. Deep Sand Bad - done properly - both display tank and refugium.
2. Refugium.
3. Home made food only. Do not overfeed.
4. I try to use the skimmer only when necessary.
5. Good, smart, water flow.
6. Carbon.
7. Only DIY 3 parts additives (Alk, Ca, Mg) - no other chemical supplements.
8. Water changes.
9. RO/DI.
10. Run GFO only if necessary.
11. Filter sock only when doing maintenance.
12. I'm not adding anything that I cannot test for.
13. I'm striving to run the system as natural as possible.
If I forgot something I'll edit the post and add it.