The best way to please your boss is with a good attitude. Just as you shouldn't bring your work home, you shouldn't bring your personal life to work. You're there for one reason, to get the job done. It doesn't matter what's going on at home, what matters is doing your job and doing it right.
You must be on time. When you're late, you throw off the entire workplace. Unless you have a true emergency, be there when expected. When it comes to breaks and lunches, be timely here, too, especially if others are waiting to take their breaks and lunches and can't leave until you get back.
Follow the dress code. If you have to wear a uniform, make sure it's clean. Don't wear clothes to work that you'd wear for a night out on the town.
Don't stand around on company time, talking, drinking coffee and doing nothing. Do these things on a break.
Don't be the Official Gossiper. Nothing brings down the morale more than a rumor mill. Chances are, whatever your saying isn't true anyway, so don't add to the rumors.
When you can, go above what's expected of you. Work extra hours when you're asked to. This will mean when you need time off, you'll be more likely to get it.
If you're having trouble with some aspect of your work, don't wait too long to ask for help. You're not going to endear yourself to your boss, if you wait and they've got five hours to fix your mistakes before a deadline. They will respect you more for asking for help in a timely manner.
This may seem strange but leave when your day is done. It's annoying having people standing around chatting when they should have left an hour ago. You're in the way, go home!
If your boss does something, which makes your life easier thank them. Being in charge is a thankless job a lot of the time and knowing you're appreciated is helpful to everyone, even the boss.