I faced a similar situation lately.
Hint the target's best friend about your feeling, the best friend must be on your side. Best friend will spread news over. If target is interested, you can expect her to get closer to you. She should txt/contact u more frequently.
Organize an outing which involve alcohol. Under alcohol influence and if she is interested in you, she will show body contacts (create chance for you).
The Beginning: Hold-Hand
You have to identify hints she drop like when she tries to hold your hand when you try to cut through the dance floor. Hold on the hand and don't let go. If she don't resist even after when you reach your destination, go on the step two.
The "high" factor
Use alcohol as an excuse to get more body contact. If she allow you to rest yourself on her, half the battle is won. If she started the ball, you stand a higher chance.
Sealed with a kiss
With such close body contact, peck her on the fore head. DO NOT aim for the lips immediately. If she accepts the kiss on the fore head, look her into her eyes. Tell her what she thought about you. If she does not back off, go to next step.
The confirmation
Next day, text or call her to apologize, and ask her if she had a hang over. Slowly change topic. Pop the question.
Back up plan
If all else fail, blame it on the alcohol.
I should have use this eariler...she allowed me to hug her..omg....i almost want to kiss her...but i dnt dare..FFFF