An excellent habit that I've noticed among professional players of the game Magic: The Gathering is asking the question "how do I lose?" - a sort of strategic looking into the dark.
Imagine this situation: you have an army ready to destroy your opponent in two turns. Your opponent has no creatures under his command. Victory seems inevitable. And so you ask "how do I lose?"
Because your victory is now the default, the options for your opponent are very limited. If you have a big army, they need to play a card that can deal with lots of creatures at once. If you have a good idea what their deck contains, you can often narrow it down to a single card that they need to play in order to turn the game around. And once you know how you could lose, you can plan to avoid it.
For example, suppose your opponent was playing white. Then their card of choice to destroy a big army would be Wrath of God. That card is the way you could lose. But now that you know that, you can avoid losing to Wrath of God by keeping creature cards in your hand so you can rebuild your army - you'll still win if he doesn't play it, since you winning is the default. But you've made it harder to lose. This is a bit of an advanced technique, since not playing all your cards is counterintuitive.
A related question is "how do I win?" This is the question you ask when you're near to losing. And like above, this question is good to ask because when you're really behind, only a few cards will let you come back. And once you know what those cards are, you can plan for them.
For example, suppose you have a single creature on your side. The opponent is attacking you with a big army. You have a choice: you can let the attack through and lose in two turns, or you can send your creature out to die in your defense and lose in three turns. If you were trying to postpone losing, you would send out the creature. But you're more likely to actually win if you keep your forces alive - you might draw a sword that makes your creature stronger, or a way to weaken their army, or something. And so you ask "how do I win?" to remind yourself of that.
This sort of thinking is highly generalizable. The next time you're, say, packing for a vacation and feel like everything's going great, that's a good time to ask: "How do I lose? Well, by leaving my wallet behind or by having the car break down - everything else can be fixed. So I'll go put my wallet in my pocket right now, and check the oil and coolant levels in the car."
An analogy is that when you ask "how do I win?" you get to disregard your impending loss because you're "standing on the floor" - there's a fixed result that you get if you don't win, like calling a tow truck if you're in trouble in the car, or canceling your vacation and staying home. Similarly when you ask "how do I lose?" you should be standing on the ceiling, as it were - you're about to achieve a goal that doesn't need to be improved upon, so now's the time to be careful about potential Wraths of God.