Make a list of the things that bothered you when you were a kid and try not to do them. You're probably going to be very busy that day, but I would ask any good candidates to stick around for a chat.
Here are some things that I would do if I were running a showcase:
- Use your website to communicate all important information.
- Clearly list the deliverables, and deliver them when promised (e.g. written eval, online stats, etc.).
- Publish the schedule on your website and stick to it as closely as possible.
- Publish the skills reps (e.g. 10 hacks, 6 ground balls for IF, 6 pop throws, etc.).
- If sim games, list any special rules.
- Clearly state your return policy (e.g. weather postpone/cancel, player injury, family emergency, etc.)
- Explain any applicable recruiting rules, especially if you're inviting NCAA coaches.
- What type of bats you're allowing. Don't let them sneak in a BESR.
- Make an FAQ.
- Get as much on-field help as possible. Even non-baseball people who can run errands, move people, etc.
- Schedule proper warm-up time before skill stations.
- Allow 2 attempts at the running events.
- If you're playing sim games, limit the number of players by position.
- You might want to create a Twitter account just for the showcase, or for your school's baseball showcases/camps.
- Invite someone from Admissions to set up a table to answer questions.
- Post announcement on all the free message boards that cover baseball within n hours of school.
- Send website to presidents of high school coaches associations.
- Send website to travel team coaches.