Here's how I like to cut a 1-pound block of mozzarella into 18 sticks. First, cut the block into 6 equal slices along the longest dimension. (You can cut it in half first and then each half into thirds, to make it easier to judge the measurements.) Then, cut each slice lengthwise into three sticks. String cheese tends to be MUCH more expensive, but you can use it if you want. Cut each stick in half crosswise to create two shorter sticks. They'll be a little stubbier than the classic, but they'll work fine.