If your toes are bunched up and curled at the toe end of your boot, that's a key sign that your boots are too small. Most hikers will get 1/2 a size larger than their regular shoes to compensate for wearing the right socks for hiking. Another way to tell is if there's so much pressure on the sides that your toes are slightly overlapping each other. You want your shoes to have a snug fit but not too tight, where you'll start experiencing pain and hot spots while hiking.