<shuddering at seeing "Slappy,Eva" written above>
Advertising is one of the last phases of the process. First, you have to identify your target market, where they live & work, what ages, likes & dislikes, buying habits, determine which medium is best at reaching them, etc. etc. It isn't as simple as running a single magazine ad. (Wish it were!) Although that might be a good suggestion for some products/services, it wouldn't work for all.