The necktie is probably the most misunderstood and most abused article of apparel in a man's wardrobe, according to Mortimer Levitt, author of ''The Executive Look: How to Get It, How to Keep It.''
Noting Oscar Wilde's quote, ''A well-tied knot is the first serious step in life,'' the author says barely 10 men in 100 know how to knot a tie properly: ''The one mistake all men seem to make is to pull the knot too tight, causing the tie to wrinkle excessively and eliminating any possible vestige of elegance.''
Color coordination is easy, says Mr. Levitt, and the key is simplicity. If your shirt is blue, the tie should have blue in it. If the shirt is white, the tie should have white in it. If the shirt is tan, the tie should have tan in it. It is possible for a tie to have three, four, or even five colors, so long as one color clearly picks up the base color of the suit or the accent color of the shirt.
Most men, claims Mr. Levitt, wear two and even three patterns. If the tie is patterned, wear it with a plain suit and plain shirt, he advises. If the suit is patterned, shirt and tie should be plain. ''Never mix patterns,'' Mr. Levitt says.
Although there is an infinite variety of necktie patterns, there are only a few basic weaves. For business, he suggests knit, grenadine, rep, ottoman, Shantung, printed foulard, and macclesfield. For dress-up, choose peau de soie (a matt-finished satin); French natte (a satin basket weave), and Jacquards (satin patterns on a plain ground).
Because the bow tie causes frequent comment, Mr. Levitt says, it is not recommended for men who need to be taken seriously by their clients - a CPA, an attorney, a financial advisor. The bow tie is for artists and men in fashion.
Tie widths range from 21/4 inches to 41/2 inches, depending on the fashion. He recommends staying with the classic look, about 31/2 inches, which will always look good.
Don't overspend on ties, advises Mr. Levitt. ''The necktie is the one item on which both men and women frequently are grossly extravagant.''
He says imported silk ties should cost no more than $15 to $17.50. Polyester ties in a quality similar to silk sell for one-third to one-half less.