Going back to a supervisor for clearer directions can be daunting. Most supervisors who are poor communicators don't like to be confronted with their failing and are apt to blame you for not paying sufficient attention. Accept that you're opening yourself up to possible annoyance. There's no choice, however, since failing to get complete direction can result in your failure. You can mitigate this by tailoring your request to the type of supervisor you're facing: someone who micromanages, someone who is intentionally or unintentionally vague; someone who speaks only in generalities; or someone who overloads you with projects. By offering to put your questions in writing you may push a reluctant supervisor into acquiescing and giving you the feedback you need.
TACTICS
Attitude: Be grateful and diplomatic but persistent. You need to get sufficient direction, so you can succeed at the task. Failing to get clarification sets you up for failure.
Preparation: Determine whether your supervisor is a micromanager, vague, generalist, or overloader. Prepare your own materials in advance in case you're forced to deal with this via email.
Timing: Make this approach as soon as you realize you need further direction. Don't make this an ad hoc approach. Schedule the conversation for a time when your supervisor should be able to give you some individual attention.
Behavior: This can be done over the telephone but make sure you follow up with an email either confirming the results of the conversation or outlining the information a busy supervisor didn't let you convey verbally.
ADAPTATIONS
This script can be modified to:
Get feedback from your supervisor on your team's or your own recent performance.
KEY POINTS
Express gratitude and be willing to humble yourself to get the information you need to succeed.
Target your approach to the type of supervisor you're facing.
Be ready to outline your planned approach in order to have a foundation for discussion.
Force a paper trail if your supervisor doesn't offer you sufficient time to answer all your questions.