Flight instructor Max Trescott writes that with so much information presented by modern electronics, pilots can lose focus of the most important data. Keeping track of altitude only takes a moment and can save lives. "Some pilots like to circle the target altitudes on their charts so they're easy to spot. Others write down a list of fix names and target altitudes. Whatever technique you use, be sure -- dead sure -- of your target altitude before you begin your descent," he writes.