This is the paper we used when planning the CAGE match last year. It was a invaluable resource. We wanted a small friendly competition that teams could use to introduce new members to FRC and have a some fun and this paper really helped us out even though we had no intention to have an event like IRI (wow that's a long sentence.)
How to IRI by Chris Fultz
My advice would be, keep things simple for the teams. Easy load in, comfortable pits, affordable concessions ......
Get the best people possible to help you. Don't be afraid to ask the best, most will be glad to help out.
Parents, parents, parents. No off season event would be possible without a lot of parental help. Recruit them early.
One guy has to be the general and be prepared to take charge. Taylor is our 4 star!
Don't try to make it a fundraiser, keep the price affordable. Try and break even, profits will come down the road once you're established.