HOW TO IMPROVE YOUR BUSINESS MARKETING SYSTEMS ?

SIR, in reality i am a student of literature in NU ML Islamabad Pakistan but my father is a businessman and sometime i got opportunity to deal with the customers  so my personal experience is that if u want to make your business profitable then be smart towards the customers and gives preference equally both large one and small one .  and never give up any customer even you earn very little from him/her.