For me, living a boring life is the best for my mental and physical health. So, some of the 'boring' things I've been doing lately are:
-drinking lots of water, I carry a water bottle round with me (and don't care whether this looks a bit childish!)
-eat very regularly, so breakfast, lunch, dinner and two snacks so my blood sugar is stable
-wash my hands a lot, especially in winter, I get far fewer colds now
-get at least 7 hours sleep a night (most nights, no staying up watching films/reading til 2am)
-one cup of tea a day and no more caffeine, helps with sleep (see above), don't drink anyway
-take medications on time with a chart so I don't forget, same with vitamins
It sounds like a really dull life, but I find if all this is taken care of, I function a lot better. If I start missing meals, or forgetting to take my medicine, or not drinking enough in the day, I get headaches, feel worse mood-wise, am less resilient. It's the opposite of spontaneous in some ways but I don't care, I know what works for me and instability doesn't!