Act fast. As soon as you realize you’re at fault, step forward to say so. Otherwise, “before you know it, you’re apologizing for the tardiness of the apology.”
Face your mistakes. If you’re feeling guilty, “the least you can do is say so in person.” Apologizing face-to-face rather than through e-mail shows sincerity. But if confrontation really frightens you, “putting an apology on paper lends more weight.”
Choose your words carefully. Make it clear you know that “you screwed up.” Avoid halfhearted apologies like ‘My bad’ or ‘I’m sorry you’re upset.’ But be sure to use the “first person”—as in “I made a mistake.” The injured party wants “to see you suffer”—at least a little.
Make a gesture. When “sorry” isn’t enough, give the person you’ve wronged “something thoughtful.” Sometimes just “flowers or wine” are enough.
Source: Allure