Ich happens. For most reefers, its almost impossible to keep out of your tank, while balancing this being a hobby vs a full time job (My opinion, no need to flame). As a bunch of folks mentioned, good water chemistry, high quality food, and some supplements and most healthy fish can keep it in check on their own.
I had a pretty bad ich outbreak when I started and didn't recognize it quick enough, lost about half my fish, since then, I've added a UV filter (questionable if this helps but it makes me feel better), made sure my water has stayed in check and done supplementation, as I mentioned. What I do for feeding on a weekly basis:
3 days x Frozen Mysis (1 day soaked in selcon, 1 day soaked in vitamin c, amino acids and garlic, 1 day plain mysis) - with the selcon I dump it right in, with the vitamin cocktail, I drain the excess water through a coffee filter and then feed the mysis after a quick rinse.
2 days x Larry's Reef Frenzy
2 days x Specialty food made by my LFS
I try to mix it up so its not the same food the same day every week, and I do feed pretty sparingly so I haven't had any algae blooms due to the high nutrient diet.
Since I started this regimen, I've seen one maybe two instances where a fish showed some signs (in both cases it was a orchid dottyback and the other fish were un-effected). Both times, within about 3-4 days it cleared up completely and the fish has been fine since. I've not had any other losses in the tank except for a cardinal that was bullied by its mate.
Maybe won't work for you since every tank is different but it worked well enough for me.