This is an interesting node... and it is quite a challenge to write something on this subject. Lying, after all, is the ultimate "hot-button subject".
How does an honest person lie, and why?
First, let me disagree with Nanosecond, whose writeup implies that he does not appear to believe that there is such a critter as an "honest person". Rather, "honest", in Nanosecond's interpretation, means simply "so good a liar as to never get caught". I just can't subscribe to this worldview. I'm cynical, but I'm not that cynical.
Now, even the most honest person will know that telling the whole, unvarnished truth all the time is not a wise practice. People aren't made to accept blunt truth - and, to be completely honest would mean doing away with many politenesses that are absolutely vital pieces of social lubricant. After all, would you want people to tell you 100% honestly what they thought of your clothes, the way you look, the way you perform your job, etc.?
A wise person thus knows that it is possible to put too high a premium on complete honesty. Sometimes, the truth must not be stated bluntly. It must be packaged.
This, of course, begs the question: "If it is all right to conceal the truth, then when does concealment end and lying begin?"
To withhold the truth is sometimes a wise act. To present falsehood as truth is always wrong.
This is where I see the honest person's skill in deception: to parcel out the truth sparingly, in such a way as never to tell an outright falsehood, while not revealing that which must be concealed.
Contrariwise, a liar has no respect for the truth - he will hand out falsehoods and truth with carefree abandon, bending reality as it suits him.
Of course, the honest man has another recourse, one that has its basis in the fact that most people expect others to be liars - he may tell the truth, but do it so unconvincingly that everyone is certain that he is lying. In this way, he may achieve his goal of concealment, without compromising the essential value of truth.
In truth, as the Bard would have it, we weave a tangled web, when we practice to deceive. Nevertheless, lying really is completely unnecessary. A person of even mediocre intelligence may avoid deliberate falsehoods by the simple expedient of judiciously limiting the truths that he speaks.