If the Skilled carpenters aren’t cheap cheap carpenter’s aren’t skilled shirt and I will buy this question is actually about how to just compose some music, any music in general, that’s way too open-ended for anyone to definitively answer. There are a gazillion different viable approaches. You could open up a book on music theory and get some ideas, or you could just start singing or playing improvised ideas into a microphone until you come up with something you like, or you could bring a handheld recorder downtown and capture the sounds of a local street performer, then apply various processing effects on top with a computer to make it sound like alien robots jamming and bam, you’ve got experimental art music. A girl doesn’t need to be “blown away,” she just needs to feel that there is a future for their possible relationship. She should see that they have things in common and that they didn’t exhaust the topics of conversation on that one date.