Stop feeling guilty
Morality is a swampy ground, so it is best not to get mired in it. While the Bible is fairly clear on the ethics of lying – "thou shalt not bear false witness" and all that – precious few of us are thumping the pulpit in agreement these days. From telling your best friend she doesn't look fat in her new dress, to pretending you didn't realise that the man you were shamelessly flirting with has a girlfriend, there are countless situations in which lying really is the only option. And if you're going to do it, you might as well do it properly.
Keep it simple
The more complicated your story is, the more likely it is you will get confused and trip yourself up. Inconsistencies in your tall tale will appear and betray you. Telling your spouse that you were delayed at work when you were actually in the pub is easy enough to pull off; convincing them that the Tube was derailed, a little more difficult. Also, try not to involve anybody else in the deception. While it might seem like a good idea to get someone to back you up, or provide you with an alibi, other people are usually a liability when it comes to lying, especially if they are less practised in the art than you are.
Pick your moment
There is a time and a place for lying. If you are being asked to swear on the Bible or sign a contract you can be fairly sure it is neither. Meanwhile, perfect opportunities for lying include: saying the babysitter has called in sick, when really you just fancy staying in to watch The X Factor rather than endure another family get-together; swearing that the expensive dress you're returning has not been worn, when it's spent a night on the tiles with you; and feigning illness to leave work early for your children's school play. But be warned: there is often a fine line between lying and more serious offences.
If you believe Cicero – who argued that the face is a picture of the mind, and the eyes its interpreter – then in order to be a good liar you have to override all the physical signals that you are telling an untruth. While you are unlikely to sprout a Pinocchio-like schnozzle on telling a little fib, research has shown that liars touch their noses more than those who are honest, so avoid any suspect scratching. Similarly, if you find it difficult to look someone straight in the eye and lie to them, get over it. It is important to maintain a level gaze at all times.
If deception doesn't come naturally, don't worry. Practice makes perfect.