I've learned how important it is to keep active regularly when you have an ostomy
I've had my ileostomy for 7 months now and perhaps biggest practical thing I've learned during that time is the importance of consistently keeping active every day, even if it's just a 15 min walk.
It's been easier said than done as I'm still severely underweight and I get tired easily, but I found that if I don't keep myself physically active after a few days or so I find I end up feeling rough, lightheaded and retching, which makes me feel more exhausted and it becomes a downward spiral.
I learned keeping active increases blood flow to the bowel muscles which helps your body digest your food. I had to be re-admitted to hospital twice in the first two months after my operation because of an ileus and forcing myself to keep active by walking down the hospital corridor really helped. More recently I had similar symptoms (retching, lightheaded) and I realised I wasn't very active the past couple of days and once I forced myself to go on a short walk things started to improve quickly after a couple of days.
I can't speak for everyone as I know people's experiences with their ostomies are very different, but going for a short walk when I was starting to feel unwell really helped.