1. dissolve 30 teaspoons salt/gallon of water (30 grams/Liter, or 113.7g/gallon). This concentration is 3%. Let it match the temp/pH of the tank, and make sure to add de-chlorinator. You can also use tank water, but because you are adding a lot of salt per gallon, you will need to heat up the water. Hence, it's crucial that you cool it back down.
2. prepare a holding tank. This is a tank that is pH/temp matched with the main tank, and has been de-chlorinated. This can be a 5 gallon tub, with bubblestone, or something bigger.
3. make sure you have some sort of timer.
4. gently lift the fish out of the tank, and place into temp/pH matched salt solution.
5. start timer.
6. if the fish stays continues to stay upright, or tilts over but can get back up, keep him/her in the salt solution for exactly 5 minutes.
7. remove fish from the salt, and place in holding tank. The reason why we do this is to: 1) give the fish a place to recover by him/herself, and 2)to let the fish purge out ammonia/wastes in a place that is not the main tank.
8. if the fish starts to lose balance and cannot get back before the minutes, remove him/her and place in holding tank, as described in #6.
9. after 1-2 hours, the fish can be moved back to the main tank. He/She might still be disoriented, but should be fine.