Cramps in your toes and feet can occur due to various reasons.  One of the most common causes is dehydration; when your body doesn't get enough water, this causes an electrolyte imbalance that will affect your muscles.  Another cause can be due to ill fitting shoes.  Tight shoes do not allow the tendons in the toes to function optimally when weight bearing, and can cause them to seize and cramp up.  Another cause can be lack of exercise and flexibility.  To prevent cramps from occurring, be sure to exercise your lower extremity.  Exercise allows your tendons and muscles to stretch and contract the way they were meant to be, which keeps them healthy.