"If you followed up by email and you don't hear back, I think it is OK to follow up one more time — but that should be the max," he says. "It can be one more chance to show that you're very interested."
The subject line of your email can also have an impact on whether or not it gets opened, according to Danny Rubin, email expert and author of "Wait, How Do I Write This Email?."
"Drop names/locations and make the connection right away," he tells CNBC Make It.
If you're applying to a position that was recommended to you by a friend or a colleague, be sure to include their name along with the position you're applying to in the subject line. Rubin suggests using a short and to-the-point format, like: "Co-worker of Shirley Applegate, interested in sales position."
If the job you're applying to was not recommended by a mutual contact, simply use the the subject line to clearly state the position you're interested in. It will help the hiring manager better identify the purpose of your email and up your chances of getting a response.
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