Hmm, about to get all nestalgic...
I had always been a creative type, and loved business concepts, however when I was in high school, my robotics team had just started. They didnt do half bad (winning rookie all-star at worlds) but because of how "proud" they were they didnt have the best reputation at first with the entire student body. But in truth I think the rest of us were just jealous.
Either way, the team wanted to turn their workspace into a home and so they asked me a member of the art class to paint a mural of their logo on the wall. At first I thought the logo was really bad, but I painted it anyways. It turned out that the wall that the mural was on, was directly overlooking the computers that the web team used.
Being the opinionated little brat that I was my junior year of high school, I analyzed their work, and started a conversation with them. I thought I could do better, though I lacked the coding experience. I joined the team the following year as the co-webmaster. I managed all of the content and graphics and another student did all the coding.
We became really good friends, and ultimately with my joining the team, the entire team attitude changed and became more accepting of everyone in the school, not just the hard core nerds.
The team is now really popular, and recruits students both in and outside of the engineering classes. I now serve as a mentor for the team, responsible for the entire business and web team. And, I am more than just a creative-art-type. I actually graduated from college in Naval Architecture and Marine Engineering, and am a civilian engineer for the Navy now.
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I guess the advice that comes out of my story is that rather than trying to simply recruit students already interested in engineering to go work on the website, you should try to focus your efforts on those non-engineering students in your school, who like art, and are creative. They might even find in the process that they like engineering...which is the ultimate goal of FIRST anyways.
(maybe ask them to paint you a mural, and in the process show them how fun FIRST is.)