If you get way down, monetarily, in any form of gambling, and then, through some miracle, you manage to get back to even, call it quits for the day.
Every gambler has seen someone pull off this miracle make a heroic comeback, then continue playing and go right back down the slippery slope a second time. If you manage to get back to even after a major disaster, go home. The Poker Gods are trying to tell you something. Be happy you made it back to even. Tomorrow is another day.

 

When you win a big hand, don't jump right back in on the very next hand simply because you have a huge pile of chips.
What makes this tricky is that you do have a certain momentum going for you, one that can be used to intimidate opponents on upcoming hands. The other players all tend to back off about an inch (and that's just enough collectively. In fact, that becomes a Jot, collectively).

In general, use good sense when you have mountains of chips in from of you. Your goal is to keep them.
Using your large stack of chips to "fire-hose" money right back into the game again on subsequent hands is usually the first step in having that stack of chips shrink back down to a small stack. Continue to play solid poker. Get used to prosperity.

When you hit something big, nurse the win for a while.
This is a good rule in any form of gambling. Back off for a while; nurse the win. Let the money sit. Go for a walk.

The 75% rule.
One of the most difficult things in any form of gambling is knowing when to quit. (It's often easier to know when to quit when you're losing than when you're winning.)
One good rule of thumb is to try to take home 75% of your winnings. The goal is to get out the door with the bulk of your win - or at least a significant chunk of it - that's the idea behind this rule. (It doesn't have to be exactly 75% - it could be 66% or 80% - whatever figure you're comfortable with.) There's nothing wrong with booking a win. Again, tomorrow is another day.

Don't play last week's heater.
Today's game is a new game. Don't assume everything is going to be working effortlessly, as it may have been last week. Some players try to raise their whole game up to the level of their latest success, expecting an easy time of it from here on out. That's not the way it works. Each game is an independent event from previous sessions, good or bad.

If you win a lot of money gambling, it will feel as though it was effortless and easy. It will also feel as if it is "typical" - the way things are "supposed" to work. But it isn't typical; it never was.
When the wins happen, they tend (o happen so easily and effortlessly that it may feel like the norm. But it isn't. It's not the norm. Protect your win. Protect and guard the money you've won.
Don't get the impression that some kind of fountain of money has now been turned on - one that will be flowing most of the day and into next week.
Likewise, if it's in poker (where your cards have been running well), don't get lulled into thinking this is the way things are going to be from now on. It isn't. Don't use a run of good cards to redefine the game.
This concept applies to the long-term, too. If your cards have been running well for weeks on end, it's easy to start readjusting your game so that you are operating permanently at this level - planning your strategy around this wonderful new state of affairs. Always remember that there is another level, a darker level that is always lurking.