Sorry to be a nit picker thats not marketing, that is canvasssing. True marketing is all about branding, public awareness of your company and its products. Sustained marketing will build up appreciation of brand, potential customers like to purchase known brands.
Also be selctive for your marketing.Many years ago i bought a half page advert in yellow pages to advertise my business ( office cleaning ). I remember sales rep saying to me yellow pages goes to 80,000 homes in your area. The question i should of asked was how many of them make the pruchasing decisions within an organisation, not many i would guess. Foolishly and niaevely i was swayed by the big number rather than targeting my client more selectively.