Tricks to solving Sudoku include finding naked pairs, triples and quads, and using X-Wing patterns to eliminate number possibilities in advanced puzzles. Players should keep a record of the possible numbers for each cell and use the process of elimination to narrow each cell down to one possible number.
A naked pair occurs when two cells in a row, column or box have only the same pair of numbers. These numbers must be used for those two cells and can therefore be eliminated as a possible number for every other cell in that row, column or box. Naked triples and quads work the same way, except the cells that make up the naked triple or quad don't need to contain all three or four numbers, just some of them.
An X-Wing pattern occurs when two rows have a possible number that is restricted to the same two columns. That number can then be eliminated as a possibility from all other cells within those columns. The reverse, where two columns have a possible number that is restricted to the same two rows, works the same way. The four cells that make up this pattern form a box. Diagonals can be drawn between from each bottom corner to the opposite top corner, which is the basis for the X-Wing name.