I can tell you the secret of selling...
Work your rocks off day in and day out!
Sales is the ultimate high wire profession - it's down to you and only you. You have the ultimate performance measurement every day, every week, every month and every year that all other employees don't have - your own sales figures!
Therefore you genuinely reap what you sow!
There is a simple but 100% true equation for sales: E x A = P
Effort x Ability = Performance.
Low effort with lots of natural ability = possible success.
High effort with low ability = probable success
High effort with high ability = guaranteed success!
I guarantee you it's all down to hard work and effort.
Good luck - it's a great career, you will meet some great people and have some great times and earn some more than decent money.
Go for it but work your arse off!