At some point you'll probably be in a relationship that you no longer want to be in. Ending a relationship is not an easy thing to do, especially if you still care about the person and don't want to hurt them. Here's a tip to ease this process:
Always "blame" yourself for the relationship ending. For example, "I can no longer be with you because I want to be on my own/need space/want a change".
As soon as you "blame" the other person, you're giving them a chance to say they'll change. Even if you're ending the relationship because the guy's a jerk, boring, cheating, or all of the above, still blame it on yourself. You'll know the real reason for ending the relationship and he won't have the opportunity to try and convince you that he will change.
Nothing is worse than listening to someone desperately explain all the ways they're going to change so that you can stay together. Avoid this conversation at all costs.