|Pillow from Hutch Design!|
Making a blog look unique can be a trickier prospect than it seems from the outset; it's completely open-ended and can thus go very well or very poorly, depending on what your blog's goal is. Regardless, here are a number of things that you should almost never do, unless your blog's goal is to alienate and annoy potential readers:
1. Embed auto-playing music.
Music is not necessarily a bad thing; music that plays as soon as a potential reader loads a page almost always is. It makes as good an impression as yelling at a stranger, and it's one of many reasons why no one uses MySpace anymore. If you run a music blog, embed streaming media players that don't auto-play. Also consider linking out to music you want your reader to hear, so that they can listen at their leisure, rather than in an agitated state.
2. Embed unskippable ads.
No one liked pop-up advertisements in 2001, before everyone's browser included a tool to kill them instantly. Now no one likes unskippable ads, which make users wait before they can view your blog's content. Unless you have something that you know everyone wants, stick to targeted ads that make sense for your readerbase, rather than irrelevant ones that waste their time.
3. Use Flash exclusively.
The lure of Flash is understandable. It can make things pretty, it makes them detailed, it can make them wholly, uniquely yours. It also makes them drain resources on almost every modern web browser and can't be viewed on any device running Apple's iOS, making the technology dated and impractical as interface designers move into the future. Furthermore, Flash is a poor choice for blogs because it renders text solely as you design it, rather than in a medium that looks best to your reader (whose eyes might not be able to render text as small as yours).
4. Choose an obnoxious font.
Bad font choice can do wonders to hurt your credibility, especially if that font is Comic Sans MS (famously used on the tags of Beanie Babies by comic artists too lazy to pen their own text, and eight-year-olds the world over). Color combinations can be equally devastating; avoid yellow on white, for example. Stick to a more conservative font and a color combination that complements your layout, rather than one that renders your content unreadable.
5. Create a bad layout.
Deliberately terrible layouts can make for good art, but rarely convey information in an effective fashion. Stay away from noisy embedded background images, resource-intensive add-ons, and other unnecessary decorating. Make your content as accessible as possible and your readers will be relieved when it doesn't take them a month to find something in your archives.