Be prepared. It'll help you keep your sanity.
When you are going about any action, remind yourself what nature the action is. If you are going to bathe, picture to yourself the things which usually happen in the bath: some people splash the water, some push, some use abusive language, and others steal. Thus you will more safely go about this action if you say to yourself, "I will now go bathe, and keep my own mind in a state comformable to nature".
Keep in mind that Epictetus is talking about communal baths - this was ancient Rome, after all.
And in the same manner with regard to every other action. For thus, if any hindrance arises in bathing, you will have it ready to say, "It was not only to bathe that I desired, but to keep my mind in a state comformable to nature; and I will not keep it if I am bothered at things that happen".
This is some more solid, practical advice. Before you do something, prepare yourself by thinking through what kinds of unpleasent things can happen. That way, you won't be taken off guard, and you won't lose hold of your Stoic mindset.
This is of course an extension of the dichotomy of control. You are preparing yourself to be exposed to behaviour that you cannot control, and that preparion helps you to not desire to control it, or to be averse to it.
I find this to be very useful day to day. When I wake up, I am now in the habit of thinking about what can happen: the older two boys can fight, waking up the youngest. They can drag their feet, refuse to help, and be late for school. They can be generaly annoying. And I can't control any of it. Reminding myself of this before I get out of bed makes a massive difference to my happiness throughout the morning, and as a consequence, to my ability to be an effective parent.