Here's how to lay out a cement block wall yourself. Mix two parts masonry cement with one part sand, and add just enough water for a firm mortar mix. Then butter all webs and the sides of each block, using the top part of your trowel. Stagger your joints and place the open end of one block to the flush end of the next, allowing three-eighths of an inch for your mortar joint. Finally, check for level.
For more on masonry, consider:
5 Things to Do with… Cinder Blocks
9 Easy DIY Concrete Projects
Concrete and Cement: A Case of Mistaken Identities