The problem with most salesman is that they think that they are only a salesman, not the boss.
Therefore you always give discount to bait customer to buy and follow strictly to the company policy.
You should act as if you are a boss in front of the customer, let them know you have all the power to make decision so that at the back of their mind, they would not consider others to seek for advice.
As if you are a boss, you will sell at a higher price or upsell to generate more profit, you rather give free gift than discount.
If customer have special request, agree first or charge them more than market price rather than call someone who is senior for advice.
You should always remember when you are a salesman, you are the boss, you made all the decision otherwise don’t expect the client to trust you and make purchase.