Advice on banner design

Unless you have graphic design and advertising creative experience, it'd be worthwhile having someone else do it. You can use a local company, but we've found a lot of success with 99designs: http://99designs.com/users/317302. Most of thoes banners ended up costing around $200, which is much less than a local designer.

Whatever route you go, consider the following:

• Almost all advertising is passively consumed; the only reason people pay attention is because the Most Prominent Thing catches their periphery and entices them to spend a second to glance over
• People will visually follow the MPT to the second MPT, then to the third, etc; but, they won’t go to the Second or Third if they weren’t impressed by the first
• If the First and Second MPT are not nearby, then confusion breaks out and some people will go the First and others to the Second
• All of this occurs unconsciously within a fractions of a second

Keeping these in mind, you can avoid a lot of mistakes such as having your company logo be big and prominent.

Here's an article about locating, interviewing, hiring, and working with consultant graphics designers.

Do not forget to plan the banner campaign with more than one graphical option.

If you run the site where the banners will be shown, use A/B testing or just ask to the content site to provide you with as real time statistics as they can.

Good Luck!

Edited to add this URL that can be useful for you to play with your ideas. http://www.livebannermaker.com/banner-creator