JUST ANOTHER BRICK IN THE WALL
You have poured your footing, got your tools, steel-toed shoes and cement block. The footing has dried over night, and you have arisen early to get a head start on the day. Before breakfast, you tromp out to survey the previous day's work, part of which was done in the dark. You find, not only does the footing not appear level, but someone's cat has immortalized himself by turning it into a walk of fame. He has evenly placed a paw print about every seven inches.
Do not panic. You can still lay block on top of that mess. Just make sure you level off your blocks by varying the thickness of the cement layer between each row. This is not as hard as it sounds.
So how do you make sure the blocks are level? First, build up the corners of your foundation. Raise the wall's corners to equivalent heights.
Remember the string you used to mark your excavations? Retrieve it from the trash can where you threw it in disgust. Secure it to the top of the corner blocks of the row under construction. Make sure the string is taut. Use it as a guide to level each row.
The remainder of the job is easy. Simply continue to stack blocks until you reach the desired height. When you are done, let the mortar dry. You will then be ready for the next step on the road to your new addition: framing.