Doing well in sales is a matter of knowing the product you are selling.
How comfortable are you with the various guns, how they function, break down for cleaning, talking about a specific model with enough background or experience behind that particular gun [ either first hand or through a lot of research reading about that make and models quirks, recalls, reputation with buyers, etc ].
Your value is based on the above as well as your ability to work in an environment that brings people who know nothing and think they know everything about the guns they are discussing, looking to buy.
One of the biggest assets you can have is knowing how to fit the right gun to the person based on their individual needs, objectives and physical strengths.
Know how to fill out 4473's properly with no mistakes, call NICS? That's a big plus to a shop.
Got all the above in abundance? You're worth more to a gun shop than someone who thinks they want to try selling guns with little to no background in the guns they'll be selling.