In their book Go Givers Sell More, Bob Burg and John David Mann explain how you have a sphere of influence averaging 250 people — each of whom has his or her own sphere that averages 250 more people and on and on.

Therefore, according to the authors, each time you meet one new person, engage, and nurture a relationship with him or her — to the point where they know, like, and trust you — you have just increased your potential sphere of influence, not by one, but by a potential of at least 250 (and likely a great many more).

Who are these people? Well, some of them may be folks you've never met — yet. You may have the opportunity to meet them on LinkedIn.

Related: 10 social media tips for marketing and sales

With more than 430 million members to date, as the largest professional network on the Internet, LinkedIn is simply one of the most important — if not the most important social networking platform for benefits brokers, managers, and retirement advisors. Therefore, making one of the following mistakes can result in no results for you.

If you have made one of these following seven blunders, don't worry. There is resolve. Keep reading. Overcoming these mistakes is possible, but only if you take note and take action.

Mistake 1: No profile photo

Did you know having a LinkedIn profile photo gets you approximately fourteen times more views? If you don't have a picture, you're missing out on potential traffic from local business decision makers, influencers, or colleagues.

Princeton psychologists Janine Willis and Alexander Todorov found it only takes 100 milliseconds to form an impression of someone from just looking at a photo of their face. 80 to 90 percent of that first impression is based on just two qualities — trustworthiness and competence. Therefore, convey a professional image

Social psychologist, Amy Cuddy said "When we form a first impression of another person it's not really a single impression. We're really forming two. We're judging how warm and trustworthy the person is, and that's trying to answer the question, 'What are this person's intentions toward me?' And we're also asking ourselves, 'How strong and competent is this person?' That's really about whether or not they're capable of enacting their intentions."

LinkedIn is becoming more and more important for managing your reputation and establishing trust as an advisor. When you first meet a prospect or schedule an introductory meeting, the odds are high that they will search for you on LinkedIn to learn even more about you.

Mistake 2: Not completing your summary section

This is the most important section of your profile. When people are searching for you on Google, LinkedIn profiles are one of the first results that show up in a search. Don't miss out.

The summary section provides you with the opportunity to share who you are and how you help people. Write it in the first person. Make it personal.

Many professionals have been under the impression that LinkedIn is just a resume, and without a Summary section, it may look just like that.

As a benefits broker, you want viewers to know more about you, your personality and passion for this business. Use this vital space to communicate a message that resonates with viewers and let them know how you can help them. A robust profile encourages engagement.

Mistake 3: Not customizing your LinkedIn URL

When you signed up for LinkedIn, you were assigned a lengthy URL that includes numbers and your name that looks something like this: www.linkedin.com/in/your-name-8205b22. Go into your profile and personalize your URL so it's linkedin.com/in/yourname (as long as your name is still available, LinkedIn will let you know if it is or not).

When a prospect performs a Google search on a person, most often LinkedIn profiles are among the first results. Once you have that customized URL, your LinkedIn profile will likely show up even higher in a browser's search results.

Mistake 4: Not getting involved

One of the most common comments I hear is "I joined LinkedIn, but nothing happened."

LinkedIn is like joining a professional organization or trade association. It doesn't do you any good to join, pay your dues and then sit back and say, "Where's the business? Bring it to me."

On LinkedIn it's no different. Don't put up a profile and then sit back and wait. Check into groups where like-minded professionals, brokers, or advisors are hanging out. Ask questions, find out about events and start nurturing relationships.

Remember, Bob Burg's philosophy about 250 people in each person's sphere of influence? Linkedin Groups are a wonderful way to engage and connect with prospective clients, affiliates and/or referral resources and build your network.

Mistake 5: Not listing skills you would like to be endorsed for

Did you know that you can enter keyword-enhanced phrases in the Skills and Endorsements section? While many professionals think this section may be a waste of time, there is a 13 percent increase in profile views for those who list skills on their profiles. Give some thought to the skills you most want to be recognized for such as "employee and employer benefits," "voluntary benefits," etc.

In addition, as more and more people endorse you, you strengthen your social proof as a benefits broker or retirement advisor authority.

Mistake 6: Ignoring invitations to connect

How often do you receive invitations from people you don't know?

While LinkedIn suggests you only connect with people you know, I don't always agree. Sad to say, there are scammers and fake profiles out there, but don't be so quick to ignore invitations. There may be opportunities that are worthwhile (and prosperous) for you.

When you get an invitation to connect from someone you don't know, first, notice whether or not that person used LinkedIn's generic invite or took the time to personalize their request and let you know why they're reaching out to you.

If it's a generic request, before you say "no" or ignore it, review their profile. See who they are, what they do, who you might know that you have in common. You might find it's someone you'd like to know.

If so, before accepting their invite, reply but don't accept and ask them how they found you or why they'd like to connect. It's a great way to start a conversation, begin building relationships and developing the KLT Factor (know, like, and trust), which is what LinkedIn is all about.

Mistake 7: Generic invitations

One of the biggest mistakes professionals make is using LinkedIn's generic invite when they want to request a connection. You have approximately 300 characters to write a brief, personalized message. Take the time to do it. (Note: you're not allowed to include a URL to your website in an invitation).

In late 2015, it became possible to personalize an invitation you sent via the LinkedIn app on your smartphone as well.

Now go back to your LinkedIn profile and implement these pointers. Doing so helps you create a robust profile that encourages engagement and results in new and prosperous relationships in the future.