[edit] Steps

[edit] Acting Innocent

Be careful about what you say. Sweet innocent girls don't swear like sailors. Don't pick on people, never laugh at someone's misfortune or when someone gets hurt.
Be selfless. Try to be kind and help people out.
Abstain from drinking alcohol of any kind. Even the smallest bit will make an innocent gal tipsy.
Be childlike at heart. Be sure to remain true to your personality.
Don't be too loud. If you want to look sweet, don't bawl and shout at people. Talk to them, and be nice and gentle.
If someone says something rude, don't pretend you don't know what it means - that will only result in you looking stupid. Ignore it.
Smile a lot, but only if you know you can make it look real. It doesn't have to be a toothy grin, just a slight friendly upturning of your lips that eventually becomes second nature.
When you talk to someone and want them to believe every word you are saying, widen your eyes slightly. Look earnest and interested.

Wear tops that do not show too much cleavage, be modest.
Apply make-up with a light touch, if at all. A simple lipgloss and light eye shadow are all an innocent gal needs. Don't wear so much make up that it looks like a mask. Pale pink lipstick will look young and girly if you only wear a thin coat.
Have cute hair. Try curling it and wearing it in a ribbon.