I have a 2003 GMC Regency Savana 1500 Conversion van 5.3 engine that wont start

What is your question?

It starts sometimes but not at others. Battery good lights on but just decides to go dead every now and again. What can I do to figure this out and trouble shoot. Cannot safely take it anywhere with the kids and turn it off becuz it might not start back up. Sometimes if I wait and play around with the ignition and wheel - in time it starts but it drives me crazy. What could this be. Don't know where to have my husband start trouble shooting.