Plenty of maligned advice in this thread.
Temperature kills some strains of the Ich parasite and also speeds up the process.
One big water change prior to treatment, followed by an appropriate dosing of salt and bumping up the temperature to 32C (88-89F), increasing aeration to properly oxygenate the water with the higher temperature, and if you really feel like overkill - medicating with a Protozoan treatment.
Contrary to what has been said in this thread, you cannot "see" a difference during treatment, that isn't how the life cycle of Ich works. Treatments won't immediately make the white spots disappear, they're locked on until they're developed enough to drop off and attempt to reproduce, which is when they become vulnerable to heat, salt and medication.
Water changes will only remove free swimming parasites in the water and substrate which are already vulnerable to your treatment methods anyway, and it's an unnecessary step as it means you're not only causing possible stress to the fish in the process, but also stuffing around with your salt dosages for no real reason.
Continue high temperature and salt until 2 weeks after the last white spot disappears, or follow the instructions as per your medications recommendations.
To all those giving poor advice in this thread because it may or may not have worked for you in the past, please have a read up on how Ich actually works and you'll have a much better time of treating it in the future.
Understanding and Treating Ich or Whitespot.