What are the two most important and effective ways to achieve a sale of any product or service ?

Manners and Honesty (if you are honest so product quality will be better and no matter what's your product price)

Make fresh calls or Do cold calls for fully filled sales Pipeline/Funnel.

Regular in touch with existing customer base.

the bestt one is your personal relationship the second one is your regulartiry in your market with positve attitude.