Appearance what matters when someone comes to your blog and leaves with a impressive image in mind.here is the list of some cool and nice Post all over from blogosphere which  will surely help you with a better blog design:

1. First of all a large theme directory which have free as well as premium wordpress themes in it by Wphacks : 150+ Free & Premium WordPress Themes Gallery.
2. You can improve the loading time of your website by using image optimization like jpg compression by UX Booth : Speed Up Your Website with Better Image Optimization in Photoshop
3. Many themes are very popular so every one uses it like thesis but your theme should have something that gives you a different look than other blogs so by WPEngineer : 10 Checks to the Perfect WordPress theme.
4. A very nice collection of 20 selected themes which has one best thing 3-column From Blogsessive : 20 Free 3 Column WordPress Themes .
5. Many of the blogger loose their traffic by a bad blog design like i was loosing when my theme previous theme was not opening correctly on Ie6 so check out this From ProBlogineer : 7 Reasons Bad Website Design Affects Traffic.
6. As wordpress is  full of  functionality it call many things in its header which are not necessary so by removing them you can speed up your blog Loading time by ProBlogDesign : 13 Tags to delete from your theme.
7. Who all are designing their blog theme by themselves should know these things that will make the best wordpress theme by ProBlogDesign : 13 Tags to delete from your theme .
8. Before writing the post you should consider some points which improve the header SEO by  UX Booth: 5 Tips to Make Your Headings More User Friendly .
9. Make your blogger blog also look good by considering these design Blogger Buster.The top 20+ Blogger Templates .
10. You can also look at this for a good blog design by ProBlogDesign : 7 Elements to make your blog look great.
11. Here is the list of some very nice blogger Templates by  Blogger Buster : 101 Excellent Blogger XML Templates .
12. If you are using joomla This can be a very nice list for themes by ProBlogDesign : 40 Hand-Picked Themes For Joomla .
13. Increase your blog readability by using this list without readability the blog design is of no use by ProBlogDesign : 30 Ways to Improve Readability .
14. you can also use the tutorial by Tutorial9 which explain some easy improvement for your blog :9 Easy Usability Improvements for Blogs.
15. Get a stylish and noticeable RSS button  so that you can get maximum subscriber by ProBlogDesign : 110+ Free RSS Icons to Show Off Your RSS Feed .
16. If you design your blog user specific you Will never loose visitors so by UX Booth : design with user in mind .
17. Use SEO friendly themes which do 50 % of job by itself in your SEO strategy by DailySEOBlog : 101 SEO WordPress Themes – Pure Gold .

if you have any more points in mind discus with us and let the users get a better ever blog design.