As any serious job-hunter knows, it helps to dress smartly and smile at that all-important interview.
But research has revealed that a firm handshake is what really matters when it comes to impressing potential employers.
Although previous studies have shown a limp, "wet fish" handshake indicates shyness, and a firm "pump" confidence, there has been little evidence about the effect this has on an interviewer.
The US research looked at 98 undergraduates taking part in mock interviews with businesses.
As each was graded on their overall performance, five "handshake raters" also marked them on their grip, strength, duration, vigour and eye contact.
Professor Greg Stewart, from the University of Iowa, who led the study, said those who scored highly with the handshake raters were also considered to be the most hireable by the interviewers. Students with "wimpy" shakes were judged to be more timid and less impressive.
The study, published in the Journal of Applied Psychology, also found women with a firm handshake were likely to be evaluated more favourably than their male counterparts.
Professor Stewart said: "We"ve always heard that interviewers make up their mind about a person in the first two or three minutes of an interview.
"But we found that the first impression begins with a handshake that sets the tone for the rest of the interview.
"We don"t consciously remember a person"s handshake but it is one of the first non-verbal clues we get about the person"s overall personality, and that impression is what we remember."
Women were less likely to have a highly rated handshake, partly because traditionally they shake hands less than men. But when women did possess a firm handshake, they were likely to be evaluated more favorably than their male counterparts.
Body language experts warn, however, that the firmness needs to be just right, as an over zealous "bone crusher" handshake can indicate egotism, a controlling personality and a lack of trustworthiness.
The handshake is thought to have originated in medieval Europe as a way for kings and knights to show that they did not intend to harm each other and possessed no concealed weapons.