Most companies, and bosses for that matter, only know how to reprimand. Few institutions actually have a reward program for employees who are exemplary. The first way to shine as a boss is to know how to reprimand your subordinates without making them mad at you.
Don't lecture. The last thing your assistant needs is a scolding. Don't treat him like a dog that just did a "do-do" on the rug. Explain to him in a calm manner why he didn't meet the expectation.
Don't write her up. If it's the first time she's made an infraction, let her off with a warning. Don't be the tyrant boss that nobody can stand. Explain to her what went wrong, and more important, tell her how it could have been better.
Don't make a mountain out of a mole hole. Don't be a pest by pointing out every single thing your subordinates do that displeases you. Remember, they are the key to your success. You can't run the company alone, so don't act like you know everything. If you keep track of every little thing they do wrong, they will too. At the worst possible time, like in a business meeting, they may throw it back in your face.
Know when to lay down the law. When someone has been warned and it's time to write him up, do it with dignity and respect. Take him somewhere private so he doesn't become embarrassed in front of colleagues. If it's a "problem employee," then get a witness to sit in with you. Explain to the person who's being disciplined why you're taking action and then tell him how he may correct the infraction. Always give him a copy of the write-up. Be prepared for excuses and make sure you maintain control of the session.
Take each situation on a case by case basis.