I've used this checkerboard chart to crochet baby afghan squares, but you could use it for many different types of projects.
I intended this chart to be worked in tapestry crochet; to crochet it like this, you would use single crochet stitch, with each block on the chart representing one stitch. The chart would also work for filet crochet, although I haven't tested it to see how it would turn out; there are other alternatives as well, including cross stitch on crochet and other needlework techniques.
When I worked this chart with pale blue and white Bernat Softee baby yarn and a size H crochet hook, the result was a baby afghan square measuring about 10.5 wide. You can work this pattern at any gauge, so there's no need to worry about it if your squares turn out a bit larger or smaller than mine. However, if you want to use the squares together in the same project, you do need to make sure to be consistent about matching your own gauge.
Dimensions vary widely, but a typical baby afghan could measure about 30 inches square. If you'd like to crochet a 10 inch square, your stitch gauge would be about 9 sts per 2 inches when working in single crochet stitch. To make a baby afghan, you could crochet 9 different squares (use different colors to make it interesting) and then join the squares together using whip stitch or your preferred technique; you'd need three ten inch squares across and three down. Add an edging to complete the baby afghan.
Row gauge is not critical for this project, but it's a good idea to get it as close to square as possible. To help accomplish this, crochet overtop of your inactive color; it adds a bit of height to each stitch, plus it helps you to avoid having long floats across the back of your work. If you aren't already familiar with the technique I'm describing, be sure to check out a free tutorial which will show you how to get started crocheting this chart.