Who are you making that impression with: your assigner, or the other participants (players, coaches, partners, etc)?
If you’re aiming to impress your assigner, there are three main things:
Be on time; additionally, don’t skimp, shave, or short-change time on the participants. If there’s a run rule, understandable… but barring that, don’t set your own time limits to the game, whether implied or overt. The participants are there to get work in, regardless of how sloppy or how long it takes.
Apply college rules (NCAA, NAIA, and whatever mods the league is using for the summer) and be consistent in them.
Be Civil and “Casual, but Focused”. The Assigner got this gig because of a relationship he has with the coaches, so in an indirect way, you are working for the coaches. Don’t antagonize them, and jeopardize the relationship the assigner has with them because you feel you have to show off, or be some know-it-all.
If you’re aiming to impress the participants (coaches, players, fellow umpire), then the same holds true:
Be on time; additionally, don’t act all frustrated and put out if coaches confer with their players (many barely know them), or “take longer” in notifying you of changes or issues. They don’t want to be there forever, either, but they need to get the work in for their players. Don’t let minor things slow down the game for “administrative purposes”.
Apply college rules and be consistent in them. Do not call a “High School strike zone”.
Understand the Context you’re in. This is collegiate summer ball – it’s more about getting the work in, and less about wins (and losses). Do not be confrontational. Don’t be patriarchal or condescending. If they swear & curse, don’t be corrective. You don’t have to police and nanny dugouts (keeping all players in them). You don’t have to insist that each and every player that retrieves a foul ball has to have a helmet. You don’t have to peer into bullpens and ensure each catcher has a mask on. Work with coaches, not against them, or assume they’re actively working against you.
Eject anyone who “looks at you funny”, or questions you, especially when you don’t follow the above 3 points.
Tell a catcher his job, ie. “[you’re] there to protect me (son)!”
Prohibit jewelry, or make any mention of it (such as in a plate meeting) other than jewelry or bracelets cannot be worn on a pitcher’s throwing wrist, or in a distracting manner.
Make any mention of “how to approach an umpire”, such as is said at some plate meetings.
Make any mention of sportsmanship, such as is said at HS-aged / youth plate meetings.
Walk up to the plate for the plate meeting, bellowing “Coaches!!” and expect them to come running; you’re on their time, not they on yours.
Make or try “dramatic” whacker mechanics or 3-ꓘ mechanics, especially if you haven’t perfected them; as you become more familiar with your own style of mechanics, you learn when and at what intensity to implement them. Use them sparingly in college summer ball.
Think that this game is the forum to demonstrate your knowledge of the Rules; knowing the Rules, and when to implement them is important, but this isn’t the place to conduct a TEDtalk on them.
Wear your HS shirt and/or hat.
Differences?
HS – you gotta wear a shirt approved by the State (association), oftentimes navy. CSB – wear what ya want, as long as it looks presentable and professional.
HS – if you’re PU, you are “god”, and everyone else, including your BU partner(s), are subservient. CSB – you are not only equal part of an umpire team, but you come to discover that you are a fellow participant in the game, all striving towards the goal of getting work in on baseball.
HS – these are wayward youth, led by a coach, collectively competing for a Win. CSB – these are (young) adults, led by a chaperone or facilitator, who are individually developing their talents and skills in a competitive, cooperative arena.