The cutest thing you can do when you want a paragraph to ask someone out is to write form the heart and make it personal. Here are some tips:
Tip 1: Be truthful
Say exactly what you mean. If you've noticed that this person has a confident walk or hair that gleams in the sunshine or really good taste in shoes, tell them. Compliments are always appreciated.
Tip 2: Write in your own hand
Rather than writing this paragraph online or in a text, how about picking up a pen and writing on an actual piece of paper? Or, failing that, print off your message. A letter dropped through someone's door is more memorable and more romantic. Who knows? If you have a relationship with this person, they might treasure that piece of paper forever.
Tip 3: Don't be sexy
A note to ask someone out should be romantic, not sexy. Sexy comes later. So, no mentioning the bits between your (or their) legs, no outlining what you'd like to do in bed with them and absolutely NO dirty pictures. You are wooing this person, you should maintain an air of mystery and intrigue.