As someone who works retail, let me echo everyone else....never underestimate being honest. If something doesn't fit a customer, perhaps move on to something else.
Work with a customer, don't pressure them. Learn how to avoid the hard sell, and instead provide service. Most men don't like to work with a sales associate until the very end, so be aware of this, give them the space they need, but follow up with them every so often to make sure he or she is doing well.