Never ask an employee to do something you already asked another employee to do. You assign Bob a project. The day you needed it completed you realize Bob hasn’t finished… and probably won’t. You’re frustrated with Bob, and you really need it done, so you plop it on Jane’s desk. You know she’ll get it done. Maybe so, but she’ll resent it.
Never ask employees to evaluate themselves. Employees who do a great job always question why they need to evaluate themselves. Shouldn’t you already know they do a great job? Employees who do a poor job rarely rate themselves as poor. Self-evaluations may sound empowering or inclusive but are almost always a waste of time. If you want feedback from the employee, ask them what more you can do to help them further develop their skills or their career.
Never ask employees to evaluate their peers. Who wants to criticize someone they have to work with afterwards? Claim evaluations are confidential all you want; people figure out who said what about whom. You should know their performance inside-out. If you don’t, don’t use the employee’s peers as a crutch. Dig in, pay attention, and truly know the people you claim to lead.
Never ask employees to do something you don’t do. Not something you “wouldn’t” do, but that you don’t do. Would is irrelevant. Actions are everything. Lead by example. Help out on the crappiest jobs. Employees will never care as much as you do—and, really, they shouldn’t—but they will care a lot more when they know you do whatever it takes.