Being a habitual liar can get you into trouble, as I'm sure you have started to notice.

It probably started as a few little lies to get out of doings things or saying where you were. Or boasting to friends by making holidays greater and grander than they were, or family life so much more interesting than it is.

Firstly, how old are you? If you're young and still at school, that's great, you have a great chance at stopping. If you feel like you are about to lie/fabricate something, Stop yourself. Ask yourself, "does saying that actually make a difference? Or am I just going to make a fool of myself later when I forget the lie and trip myself up?"

Believe me, people won't care if you haven't read Harry Potter, but they will get pissed at you if you tell them you have. It makes them look like a fool/gulliable for believing you, so they'll stop hanging around you. Your life is just as boring as theirs.

If you can't stop lying, and you don't like it, and want to stop, I'd look at getting help from a psychologist or psychiatrist. Being a habitual liar with grandois delusions (cool name huh!) is serious, and if left unchecked can turn into a serious mental illness.

Didn't want to scare you, but if you are serious about it, you need to face it seriously.