Scan rows, columns, and boxes for missing numbers
Fill in cells with only one possible number
Use pencil marks to note possible candidates
Eliminate candidates from peers in the same row, column, and box
Look for hidden singles in each row, column, and box
Check for naked pairs or triples to remove extra candidates
Re-scan the grid after every placement
Work on the easiest sections first
Use process of elimination consistently
Repeat until the puzzle is complete