The card and the flower I wouldn't do. The best way to engage someone to ask them on a date is face-to-face. Which, if you're shy is also the most terrifying.
Pretty much you should just ask her out. When you do be direct, confident, make eye contact, smile. All the things you would do during an interview only with more personality and emotion.
"Well, then," the Cat went on, "you see a dog growls when it's angry, and wags its tail when it's pleased. Now I growl when I'm pleased, and wag my tail when I'm angry. Therefore I'm mad."