Let people know your plan. As you figure out how you're going to do something, share it. If you spend all week going in the wrong direction, it sucks for everyone - you'll have wasted your time, and your team will feel bad telling you that you missed something important. Even if your plan is perfect, by sharing it, you'll get some thumbs-up, and you can proceed more confidently (and probably faster than if you had any nagging doubt.)