There are three basic types of websites that you will come into contact as a designer and understanding the difference that advertising makes on each will go a long way in providing services to your customer.
The first is a Personal website, Second is a Corporate Business Website, Third is an online service or business.
Now although all three types may wish to use some level of advertising the way they will approach standard banners, text ads or in copy link ads is very different. This makes your job as a designer easier if you work within a vertical market but when you are providing services to a variety of different customers it is important that you understand their advertising needs before you begin or you may find that you are wasting time redesigning page layouts and suggesting unneeded extra work.
As a designer you should visit if not make accounts on many of the larger advertising platforms so you can understand the offerings of each along with the setups required. Although most ad services provide standard sizes many will provide a limited selection of custom offerings.
The three basic sizes in pixel width for most services include 160×600, 300×250 and large headers of 728×90.
Additionally you will see 125×125 square blocks which can be grouped to occupy a larger block. You will also see in content ads that commonly start off as 468×60 pixels for image and text ads but can be single lines for link ads or other various sizes.
Also make note of special requirements of each ad network. Some networks will require that their ads are placed at the top of the page or visible on the first screen of a page without scrolling either top to bottom or left to right.
Some networks have expandable rich media ads that will popout to fill the browser window when the page is first loaded or when your visitor mouses over a banner that can be distracting to a fault or it can remove function of your menus while the ad is displayed. You need to know how they work and how to limit their use when necessary.
You should then design skeleton themes for major CMS applications like WordPress and shopping cart systems or any other application front end so you can quickly add backgrounds and headers and modify css to match what your customer wants.
While developing your layouts you should adhear to the standard sizes of ads when setting sizes for your sidebars and content area while understanding that different customers will want different things.
In our three basic customers you will find that corporate customers do not normally like sidebars that match the sizes of standard advertising. Corporate customers also shy away from right sidebars and many like to maintain a total page width that is smaller then a standard site so they can provide content to visitors with the oldest computer technology.
Personal websites can be anything from your Aunt Betty wanting to post some recipes to a rock band that needs a promotional site. In other words they can be commercial or not but often this type of site falls into the custom design category. Sizes are almost never standard and the way the site looks is more important then generating income from other sources. When this is true you must tell your customer up front that they should not expect to be able to force ads into custom designs.. It is just something they will have to live without unless you can find nonstandard sizes or services that meet their layout.
Now for internet services such as a portal or a single service content site you should try to get your customer to adhere to standard ad sizes when creating their design. They may not want ads at first but if they need a total site makeover later they are unlikely to be happy. In this case you can produce blocks of content in sidebars from their own site and use in house ads to fill spaces.
So as a designer you need to know not only how to provide what your customer is asking for but also how to guide them through the decision process.
If they ask for a 150 pixel left sidebar for menus … tell them that by adding 10 more pixels to the width they open the opportunity to run not only in-house but revenue generating banners. If they say no thanks then make sure that they know that a redesign will be from scratch if it includes complex backgrounds and layer effects.
And honestly as shiny as some of the free or even pay templates are understand up front and tell your customer that 7 out of 10 times they will never match the final project correctly unless the customer is willing to have a less then satisfying final project. I have at more then one occasion told a customer there was no chance to modify their package to meet their needs and forced a choice of walking away or redesign only to have them come back months later asking me to fix what they paid for some place else.
Shiny designs are important but so is function. Make sure your content including ads can be properly displayed first then add all the pretty things to make people say wow.