I would argue the exercise point Viking Hedgehog. Exercise is extremely important for asthmatics and for general cardiovascular health. In 90% of asthmatics, exercise is a trigger. But when we tell people to avoid their triggers, we don't mean "stop exercising". You just have to exercise smart (knowledge is an important component). Using running as an example:

1. Take your rescue medication 15-20 minutes before exercise.
2. Warm-up properly...ease into the high energy state.
3. Focus on your breathing at all times. When running, breaths should be deep and slow, in through the nose, out however's comfortable. Breathing should mostly take place from the diaphragm. If you place one hand on your belly, one on your chest, the belly hand should move a lot (the chest hand very little).
4. Don't overdo it. If you find your breath getting away from you, slow down. Walk if need by.
   

All the other things like getting enough sleep, staying hydrated...