1. Patience
You'll be dealt lots of bad
hands that must be folded. It gets boring sometimes, but you have be able to sit and wait for the right opportunities. If you can't do that, the game becomes very difficult.
2. Strong critical thinking skills
There's more to poker than just guessing. There's all sorts of variables and information. You have to understand them and think your way through it while under pressure.
3. Intuition
You have to know when to pay attention to your subconscious. Sometimes the math and logic wont be enough. The little voice in your head shouldn't be ignored.