A Few Fill-in Pointers: 

• People love to be loved, but they crave
  specifics. They want to be told precisely what you love about them. So if you’re not a poet, or even a good speller, don’t sweat it. Just be detailed and real. 
• Seemingly banal choices can be surprisingly effective. (“I love your nose.”)
• Write out your fill-ins on a separate piece of paper first. It’s less pressure.
• If you’re stuck, cross out and rewrite the prompts to make them work for you.

Specifics to Consider: 

• Unexpected physical aspects (ears, voice, scent)
• Little things you secretly enjoy (the way they say hello, brush their hair, twitch in their sleep)
• Qualities you admire that the person may be unaware of (an adventurous spirit, a desire to be happy, a facility with power tools)
• Positive ways this person has affected you (teaching you to cook, helping you deal, upping your chess game)

Oh, and Also:

• Don’t overthink it.
• Don’t judge.
• Just relax. 
• They’re going to love it.