I'm a terrible salesperson
What is your reason for feeling that you are a terrible salesperson?
I do not really pay that great of attention to the needs of my customers.
If you are not happy with the type of job that you have, then it is time to find another type of job. You should always do your job to the best of your capabilities even if you don't like your job.
Caring is boring. Pass me a drink.
You should maybe not be working in that line of work if you have bad people skills. All you do as a salesperson is work with people, so you are better off doing something else if you do not have the skills for it.