I just posted this to a private newsgroup in answer to a question, but it’s worth repeating more widely. Here are six ways to make your online banner advertising better value for money!
 Context is everything; the closer you can match the ad content to that of the page it’s on, the better.
 Never overestimate the reader. A significant percentage will not realise that if you click on the banner, it’ll take them somewhere interesting. The days of “click here…” are most certainly *not* over.
 There is such a thing as “banner blindness“, despite what the online ad salesmen tell you – people tend instinctively to look away from them; however, this does not mean banner advertising doesn’t work, as the print salesmen (at the other extreme) will claim. Instead, you have to realise that if the advert is graphical, you’ve got to get your message in very quickly. Not a problem if your message has a branding element, as you can get your company name and product in instantly from the start.
 Do not underestimate simple ads. Those Google AdWords ads can (and do) get five times the click-through rate of most all-singing, all-dancing Flash creations. If there’s no real branding element to your campaign, and you want to generate traffic to your site, why not create your own text-only ads?
 Unless your banners are purely corporate branding, ensure they click through to a page on your site relevant to the message. If it’s at all possible, have them click through to a special landing page you’ve made up; indeed, every ad should be created to work with a partner landing page. If the advert asks the question, the clickthrough page *must* give the answer, instantly.
 Experiment, experiment, experiment. When booking a campaign, why not book two different types of ads (e.g graphical vs text) to run at random for a while, so you can see what works best for that site’s audience? If each has their own landing page, you can easily measure clickthroughs (and subsequent conversions) yourself.