Alternate Between Rows and Columns

Every new filled or empty cell affects two lines: one row and one column.

After making progress in a row:

1. Check the corresponding columns.
2. Add any new forced cells.
3. Return to the affected rows.
4. Continue alternating until no immediate deductions remain.

Do not remain focused on one part of the puzzle for too long. The next logical step may appear somewhere else in the grid.