How do I handle a big winning day without giving it all back?

I set a rule: once I hit my daily target, I can only take one more trade and it must be a perfect A+ setup. This gives me the feeling of "one more" while limiting the damage.

Set a daily profit target. Once hit, close the platform and stop trading. This sounds simple but very few traders actually do it. Your biggest enemy after a big win is overconfidence.