As average turnover rates continue to rise, it's increasingly important to hire the type of employee that will stay with you for the long run. Even if a candidate seems like a great fit in the interview, it can still be hard to tell if he will really work out until he starts the job. Particularly in sales, the turnover rate is even higher than average; it takes a certain type of person to be successful at the job. So how can you avoid wasting your time and resources by hiring a bad sales rep?

Pay attention to first impressions! They provide valuable insight into whether or not a sales candidate will work out. You just have to know what you're looking for. Here are five critical clues to keep in mind during your next interview.

1. They don't understand the job

Can your sales candidate accurately summarize his core responsibilities? If not, this is a strong indicator that he doesn't understand the job. Candidates should come to the interview prepared with a basic knowledge of what it is they're expected to do on a daily basis. In sales, you must not only understand your role, you must be aware of your goals, deadlines, and compensation structure. A candidate who doesn't make the effort to learn about the job before the interview, won't be the sharp, go-getter sales rep you're looking to hire.

2. They're already messing up small details

A successful sales rep needs to be detail-oriented and organized. Another telltale sign a candidate won't work out is if he's already overlooking important details in the interview process. This might include forgetting to send you requested items such as a document or reference, needing to be prompted to complete a task, or using poor spelling and bad grammar when communicating with you. Attention to tiny details, like proofreading an email before you send it, all contribute to the image you send to potential customers. A sales candidate who messes up these details in the hiring process won't get any better once he has the job.

3. They don't fit the company culture

Even the most qualified candidate who doesn't mesh with the company culture will not make it in the long run. First and foremost, employees should value your company's mission and be passionate about furthering it. Additionally, employees who don't fit the culture may feel out of place or excluded -- preventing them from becoming fully committed to their work and making it easier to leave on a moment's notice.

In the interview, ask key questions that offer insight into your candidate's personality, values, and goals. Then, compare these to your company's and use your best judgement as to whether the candidate is a fit.

4. There's an inconsistency to their attitude

It's to be expected candidates will try and put their best foot forward during the interview, but their attitude and behavior shouldn't drastically change as soon as they're interacting with someone else. This shows they are not accurately representing who they really are -- a prime reason to question their honesty and integrity.

For example, how does your candidate act in front of other employees they meet? In sales, your employees will be interacting with a variety of people every day. You don't want to have to worry about how they'll represent the company to the customer when you're not around.

5. You can feel it in your gut

It's an obvious red flag. Yet, so often, we overlook what our gut is telling us about a candidate. Particularly in sales, you have to be a likeable, charismatic person. Does the person sitting in front of you fit the bill? Would you want to buy something from him? If your first instinct is to say "no," you can bet your potential customers will have a similar response. Listen closely to what your gut is telling you about the candidate; it will help guide you in the right direction.

Avoid the costly mistake of hiring a bad sales candidate by keeping your eyes and ears open for these key signs during the interview. They indicate some critical flaws you don't want in an employee. By avoiding a bad candidate, you will save the time and money associated with turnover and build a more effective sales force as a result.

What do you think? What are some additional signs a sales candidates isn't a good fit?

Robyn Melhuish is the Communications Manager at MedReps.com, a job board which gives members access to the most sought after medical sales jobs and pharmaceutical sales jobs on the Web. Connect with Robyn and MedReps.com on Facebook, Twitter, and LinkedIn.