Type of ad?
Online advertising is offered in many forms. Different shapes, different methods, different sizes. Banner ads, cube ads, ad-words through to rotating ads. Ensure the company you have decided to buy online space from is specific in size, location etc and get them to direct you to their site so they can show you what to expect - what size and where your ad will appear. They will talk about size in pixels and to most of us we may not know what that means. So ask them what size in cm’s that is so you have a clear picture.
I strongly recommend using a marketing agency to design your ad, rather than rely on the supplier of online space to do this for you. Your marketer will have the best sales and marketing objectives at heart and understand how to portray this in a perfectly designed high quality ad. You’re spending big $$ on advertising so don’t take shortcuts. Give your ad the best opportunity to work.
Position is extremely important and the number of ads on the site is also just as important. You don’t want to advertise on a site with a blur of other advertisers. But if there is no advertiser then its likely that it may not be a good site to advertise on. 2-5 ads on a site is more than acceptable. Ensure your ad is on the homepage and if you can get right hand side position that would be optimum. Using a little flash or animation on your banner ad for eye-catching appeal is also recommended. Your message should be short and impactful and most important, what’s your offer? It should be good enough to make a potential client click on it. Your marketing agency can work with you to ensure you receive the best impact.