For the parts which I wax, I clean very thoroughly with a non alcohol-based astringent cleaner, wax it and then clean again with the astringent cleaner. I think that using Biactol helped (antibacterial), but it may all be in my mind.
Then, straight afterwards, I use pure Aloe Vera gel on all the areas shaved or waxed and basically continually on any areas which show irritation. This Aloe Vera gel is truly a life saver and really gets rid of both the redness (over a few days) and the itching (pretty much instantaneously). I buy mine from a “bio” store, though chemists should have it too. Make sure it is as pure as possible.