The basic logic followed in sudoku is to be able to sense a pattern behind the numbers that you are placing in the squares. It seems rather easy, but the more skilled players will know that simply placing numbers in squares should not be the approach to a common sudoku puzzle. Instead, you should figure out a method to placing the numbers.
This pattern will be seen in different sudoku puzzles. You should also have a head for numbers. If you are not good with patterns or numbers, then this is probably not the puzzle that you should be doing. Logically, the player of the puzzle should be able to determine which numbers should go where on a sudoku board.