Whether you're blogging or creating a website keep in mind all the different ways that your customers can view what you have to offer.
Pictures, text, fonts, and formating should look good in as many different media as possible; whether on iPads, laptops, or phones.
Different browsers render different versions of your page. Fonts are not always available on your customer's devices.
Blog readers like Google's reader also render pages differently, so after posting it is a good idea to check out what the post looks like in a reader.