Good test-taking on the SAT or ACT is part skill, part attitude.
Here's an example. Aggressively eliminating wrong answers is a skill. When good test-takers don't know which answer is right (it happens all the time, even to them), they look for wrong answers, eliminate those, guess and move on. You can learn that skill, practice it and get better at it.
But the mark of good test-takers is their attitude when moving on.
When a good test taker eliminates even one wrong answer, guesses and moves on, she doesn't feel bad. She doesn't lament that she didn't know which answer is right. She doesn't start to worry that the test is getting the better of her. There is no pity party. No "Woe is me." Her attitude is,
"OK. Got rid of one and guessed. Next question."
Good test-takers have the same attitude towards tests that successful college applicants have towards the entire process. They try their best and they're happy with their effort, even if the result isn't perfect. And they know that as long as they keep applying that effort to other areas of their life, everything is going to work out just fine.
You can learn that attitude, too.