You can join your crochet squares with a very visible join on the right side of your project. You might choose to use this if you want to use a contrasting color to outline your squares. This is the joining method I used for my free crochet pattern, Ramona Scarf, shown below. Get the free pattern by clicking here.
Watch below to learn how to join the squares for the Ramona Scarf, or for any other project you are doing that needs this type of joining technique!