If you want to get your crush's attention and admiration, then sending him or her a cute message or paragraph can definitely work. I know, because it worked for me!
I liked this girl in the year above me, and I wasn't sure at first whether to approach her or like try and impress her from a distance and get her to talk to me first. In the end I decided to write her a cute little note to let her know how I feel.
The thing is, I was already flirting with her and stuff, so I think she already kind of knew I liked her. I think that was important, because if it was just a random note out of nowhere, she might think I was being weird.
We were actually on a field trip and traveling back by coach and she was sitting next to her best friend then I passed her over this paragraph I had written on the coach that basically said how I thought she was fun and beautiful and pretty much awesome in every way.
At first she was kinda shy and didn't say much, but a few weeks later we had our end of year dance and she kissed me twice that night, so it was a definite WIN.
As for what to write in your paragraph - it really depends on your crush. Everyone is different. Just use the info you have about him or her to guess what you think they will respond well to.
Don't be too desperate or cringey... Just be like "hey, I just wanted to say you are awesome because of whatever... And going to this field trip/classs would suck if it wasn't for you." Also ask if he/she wants to spend some time together, like getting food or watching a movie,
