Aha, and now we have discovered the meta logic puzzle of this site. How do they do it?
Solutions to this meta puzzle have been offered many times in this forum, and the only thing I can add is to point out a few things that don't work.
Reading the clues backwards real fast does NOT help you resolve the single or double XOR positive relationships.
Filling in the grid with random entries, then printing out a screen shot quickly, and examining the result under a UV black light does NOT reveal a secret watermark indicating the incorrect entries.
In a 4x7 puzzle, finding the clue number of the "Big Negative" clue (the one that lists 7 things that are all different), and holding down the ALT key and tapping the F4 key lightly the same number of times as the clue number does NOT reveal any part of the solution.
The following things help a lot.
A good memory for backstory attributes, clue structure, and labels.
Having a sixth and seventh sense about clue processing order
Time (lots of it)
Doing lots of puzzles in the same category within a short time frame.
Getting great pleasure from solving familiar puzzles over and over again
As for stamina, caffeine helps, but check the table again for players who are really dedicated. Four hours a day might be a lot for some, but it pales in comparison to players with the best stamina.