That's a very good question! Sounds like you tried to approach it in a straightforward and sensible way. But since that official won't tell you what you need to know, maybe you need to be a little indirect this time.

If this transfer is to a different school district, try contacting your state department of education. They might have someone who can tell you what the rules are for transfer, and those would give you clues about good reasons to include.

If this is a transfer within the district, then maybe you want to go down to the district office again IN PERSON and talk to a different official so you can approach it a little differently.

What follows is a bit annoying because it shouldn't have to come to this, but sometimes it does. People generally like to feel needed and often are more helpful when there is more relationship.

To create that relationship, you can try the "help me" approach. Take your application to the official and ask for help filling out the application. You don't have to play dumb, but since you are truly hesitant about how to fill out parts of the application, you can let that show. Before you go, study up on all the reasons why your son is a good match for the school you prefer. For example, does it have a good art program and is he particularly interested in art? etc. Then, while you are filling out the application with the official, you mention all the reasons why you're hoping your son will get into the preferred school and how excited he is about the possibility. (I'd stay away from claiming one was a "better school" than the other, since districts have to fill all their seats.) When you get to the section about reasons, you ask for help with wording from the official.

This is kind of manipulative, but it's not dishonest. You genuinely need help, and this might get it for you.

If that fails or if you'd prefer a more direct approach, call the school you prefer and ask for the contact information of the PTA or from another parent leader. Explain your situation, and ask if they know of anyone who's transfered into the school who would be willing to talk to you.

Good luck!