remove fish to quarintine and do hysposalinity for roughly 6 weeks and leave tank empty to make sure ich life cycle is broken. or you can try kik-ich some people claim to have had positive results. i personally did not and just decided to ride out the storm and most fish cleared up on there own.
im sure you will get many different suggestions so good luck
What kind of fish do you have? Is it just a few spots, or heavy infestation? Sometimes it's more stressful on the fish if you chase them around and try to catch them. Some people just say leave them in the tank, feed garlic, selcon, get cleaner shrimp, etc and it will clear up on its own.
The only time I had any problem with some type of parasite outbreak was early in my softie tank's lifespan (just broke down tank and sold all livestock last weekend after 2 years).
If the infection is light and the fish do not appear overly stressed, you might consider adding 2 drops / day of garlic supplement. My fish fought off their parasite infection after about a week or two when I did that.
After that, I kept supplementing 1 drop / day (at feeding time) ever after, and never saw another outbreak. Softies seemed to like it too.