Sleep!
Being overly tired or tired over a long period of time can definitely increase the frequency of seizures.
One of the easiest and most important things you can do to help your child is to make sure they are given the opportunity for a full night's sleep. The amount of sleep each child needs is different and varies by age. As a general rule, older children need 9-10 hours, younger children 10-14. Babies need even more. Talk to your child's pediatrician for more specific guidelines for your child.
If your child does not sleep well or is restless, you need to discuss this with your child's doctor. There may be an underlying sleep disorder that is ultimately causing the seizures. Your doctor may recommend conducting a sleep study to check for sleep apnea or other sleep disorders.
Lastly, if you have an older child, make sure he or she understands the importance of sleep. All night cram sessions, late night jobs and parties are not good ideas.