If your boss routinely delegates projects without telling you how things should get done, and then picks apart your work and asks you to start over, you need to get proactive. Asking for more clarity upfront is a place to begin, but if that doesn't work, try figuring out your boss' viewpoint in another way. When you're asked to handle a project, draft a preliminary plan for how you intend to approach the task. Set up a meeting with your boss to review it and see what he thinks. Incorporate his feedback into a revised plan and share that with him again. Keep doing this until your boss signs off. If you do this often enough, your boss may eventually realize that he can save time by being more specific at the outset.
Source: Harvard Business Publishing : Today's Management Tip was adapted from the Harvard ManageMentor Online Module: Time Management.