the famous story about asking G-d for a 'sign' is about Gideon, a man whom G-d called to be a Judge over Israel...
you can read the passage about him
here in Judges 6.
I think our ways of asking for "signs" borders more on superstition, divining, and wishful thinking than anything else. Gideon heard a command directly from G-d and only then did he say "show me that this command is from you"... he didn't say "show me a sign about what you want me to do" because G-d had already made it crystal clear what He wanted... Gideon just had to have faith and respond. I don't think asking for broad, aimless signs is really the way to go.
Sometimes life is not spelled out as clearly as we'd like. But I think that at those times we grow in faith and use the Scriptures and seek for the Holy Spirit to guide our actions. Seeking G-d's will isn't a magic trick... it's a journey and it takes little decisions along the way.
A parable...
A son goes off to university and calls his father constantly. Of course he loves his father and wants to please him.
He asks "Father, which classes should I take? where should I live? Tell me what I should do in my life. I don't want to get it wrong! Tell me what to do!"
The father reassures his son, "I love you. I trust you to make this decision and I will support you in whatever you do because you are a righteous son and you want to do what's best."
The son begs and pleads. "No! Don't tell me to choose! Tell me
what to choose. I need to know what you want for me!"
And the father has to tell him again, "Son, I love you! I want you to follow your passions and dreams. those are all such great ones. Nothing is wrong with them. I won't stand by and watch you make a dire mistake or sin... but I want you to know that you have the freedom to choose and I will help you and support you in the path you take. This is a time for you to grow and mature."