The key to convincing someone you are telling the truth is to keep a balance of fact and fiction.
Decide if what you are lying about is worth the effort and the potential consequences. It is a personal decision. You need to be realistic with yourself. It is easy to become a compulsive liar and ruin your life. Under what circumstances are you willing to risk damaging relationships, reputation, and future opportunities and do the benefits of telling the lie outweigh the risks?
- If you know you're going to have to lie, think of some specific true thing (place, person, event, story) that your lie will fit into and use those details if you are questioned. This gives you a bank of specific details to draw on so you don't have to keep making things up as you go along. The more things you have to lie about to support your original lie, the more likely you are to be tripped up. Lying is a bit like chess--you must always think ahead. Anticipate what the person you're lying to is going to ask, and be prepared with a response.
- Force yourself to believe your lie is truth. This will make you naturally act as if you were telling the truth. The trick is convincing your sub-conscious mind that you're telling the truth. An example of this may be, "Did I wreck the car? Well, I drove it into a wall. So, the wall wrecked the car. I just moved it!" In the immortal words of George Costanza, "It's not a lie if you believe it's true." This works well when your situation is quite ersatz. Alternatively, try imagining that you didn't. You're somebody else, who DIDN'T wreck the car. Pretend to be that person. Convince yourself that you're the person that didn't wreck the car.
- NEVER use big words or speak in a way you are not used to. If an average Joe sounds like he's reciting a thesaurus when you ask him how your car got that huge scratch, you'll know something is up.
- Slide the lie into a casual conversation. It's better to lie to the person in advance than have him question you later on the same topic. That way, the victim's mind has hours, possibly days to fill in the blanks, and if he/she does come back to question the story, you'll have a much easier time as your victim starts in on you. If the victim discovers your misdeed before you explain yourself, they'll have time to deduce what has happened with a certain degree of certainty before they ever even question you.
- Example: Joe, Bob's roommate, walks in the front door, Bob, looking up from the television screen is told by Joe that the dog ate his sandwich when Joe actually did. Bob walks into the kitchen, discovers the sandwich is gone and shrugs. However, if Joe never said anything, Bob would come out of the kitchen angry and assumed Joe ate his tender, delicious, mid-morning snack, which in turn makes him angry and less receptive to anything Joe has to say in his defense.
- Look the person you are lying to in the eye. Don't look around, but don't stare either. In a normal conversation people do avert their glance from the other person's eyes naturally. People in the act of telling lies tend to do things in the extremes. Either they try to avoid eye contact as much as possible or they never break eye contact. In a normal conversation your eyes will move and you will look away to think, but otherwise you will maintain eye contact. Don't touch your head with your hand, or hold your palms up. Keep your palms at your side, and leave them there. There are many subliminal messages people send when lying. Learn what they are and how to avoid them. Another helpful tip is to not stutter or get flustered. Some people blush or begin to stutter, because in some cases the subconsious panics. Keep calm and collected. Even go through what you are going to say in your head first. Therefore, you won't have to improvise. Most professional lie detectors (e.g. law enforcement professionals) know what they are, and you should, too. The cops will make small talk with you to establish what your "normal" behaviors are. When they get down to the serious subject matter, they look for deviances in behavior. Polygraph machines work the same way.
- Practice lying in front of a mirror or video camera. Observe your facial expressions. Try making your eyes go big and letting your mouth hang open a little for an innocent/shocked look. Also, practice looking like you're holding back tears. When you smile, show your teeth a little and crinkle up your eyes and cheeks. This is a 'sincere' smile, an ear-to-ear one.
- Make a truthful admission. If you sense that someone else suspects you of lying, admit or make them suspect you of something small or untrue. They will take the bait and think that that is all you were lying about.
- Play dumb. Coming off as too stupid to lie is a great defense. Lie as badly as you can about something small, but never actually admit to doing it. You will be free to lie about much bigger things and never be suspected.
- Follow through. Never forget about your lie, and treat it like it actually happened. Mention it in conversations the way you would if it was true. Silence about a certain subject can arouse suspicion, especially in retrospect.
- First, you will find that lying is much easier if you have a neutral reputation towards whoever you're lying to. This means you cannot have done anything bad to them that they can recently recall. This will prevent immediate suspicion about whatever you're saying and they will listen to your story and believe in you a bit more.
- Think about what questions the victim of your lie will ask when you next see them. For example: You tell your parents you're going to the movies with a friend. But you're really going to a concert with your girlfriend. Logically they're going to ask about what was in the movie you watched. Before you go, Google a summary what was in the movie; along with the climax and you can say it was your favorite part. Make sure to not sound like it was rehearsed.
- Make a lie that cannot be linked with anything anybody can relate to or look up. An example would be that you wanted to get out of school and you're "sick." Obviously you're going to have to go to the nurses office and explain what's wrong. Your school nurse usually will only be able to check your head with a thermometer. So saying your stomach hurts from eating beans at lunch can't be checked or related to because the nurse didn't eat lunch with you and she can't open your stomach and look inside. The rest of the lie is in the bag.
- If possible, combine your lie with the truth. Say your mom heard you talking on the phone about how drunk you got last night. She confronts you about it. Of course, you cannot completely turn around and say you didn't touch alcohol. Instead, include some of the truth while downplaying it. If you said, "What? I didn't drink!", say, "Yeah, Mom, they had a bottle of scotch after work... I took like one drink and I was out. It was gross."
- Insult the other side. If people ask you about a lie, they expect you to be defensive, so naturally you should go on the offensive. Let's say you borrowed your dad's car and screwed it up somehow. He comes home, sees it, and says, "What happened to my car?" Instead of saying, "I don't know, I didn't do anything," say, "I dunno. It was screwing up the whole way over there, I had to pull over like twice and check out the engine."
- Do not try to distract the other person. It is very obvious when someone is trying to change the subject. If you keep talking about baseball while they're trying to figure out where their money went, it will be obvious you are nervous and don't want to talk about it. Instead, talk about their money for as long as you normally would - this is another reason why it is important to learn how you act when you are telling the truth.
- Body Language: when people suspect some one of lying it is normally due to clues that the person is giving off with body language. Many of the things police officers look for when they suspect someone of lying are the same things we do when we are under stress. Thus giving off confident body language can help convince the person we are lying to that we are telling the truth. The general rule is spread your body out. Don't cross your arms and don't cross your legs. Instead spread them out. Don't tilt your head down but instead keep it level. Don't fidget, don't play with you fingers, hair, pen or anything, just keep you body still and relaxed. Relaxation is important; if you are stiff you may give it away. Keep a calm level tone of voice, if your voice raises you will give it away. Also do not place anything between you and the person you are lying to. If you are holding something, and have to put it down place it to the side somewhere. By doing these things you will be giving the impression of confidence, which is the opposite emotion people normally have when lying. This makes the lie much more believable.
- Fake memory loss is an excellent way to lie. For example, if your mom asked you what you did at lunch and you had been making out with the girlfriend you wern't supposed to have, instead of just saying "Uh...nothing special" say something more like "Uh..I can't remember...stuff...talked to some friends" sounds like what a parent expects to get from a teenager. Plus you can't really get caught in memory loss lying. Try looking a little confused as you feign memory loss it'll make it more believeable.