Transformational comedian Kyle Cease has a hilarious bit that I've seen him do a couple of times at The Shine:
"You ask the Universe to show you a sign that you should leave your job... and the next thing you know you're driving down Leave-Your-Job Blvd, and you're like, 'I wonder if that was a sign.'"
His point: asking for a sign IS the sign that you're looking for. If your job was in alignment with your purpose, you wouldn't be thinking about leaving it nor would you be asking for a sign.
Often, it's not a sign that we need to ask for--rather, it's the courage to follow through with it.