The new default theme is called twenty ten and it is light years ahead of the old default one. From within the admin you can change the header or add your own. You can change the color of the background or upload a background image. Often, your webmaster will do this for you, but it is fun if you want to do it yourself.
Changing themes is as easy as clicking ‘activate’ once it has been installed and up loaded. One caveat, there are literally thousands of free themes available, however, not all of them are nice. Some have paid advertising of their choosing on your blog and they get paid, not you. Others have malicious codes installed that you would not see or recognize, so beware. Doing things yourself is fine IF you have enough knowledge and experience to know what you are really doing. I am trying here to lead you into the areas that you can do yourself and stay away from anything that would be harmful or a security breach.
WordPress.org vets their themes quite thoroughly so you are fairly safe getting a theme from them. Send the link to your webmaster who will upload it for you. If you want your blog to closely match your website, talk to your webmaster.
Themes sometimes come with options that enable you to do different things, and when you install a new theme you may have to place your widgets again. Widgets and plug-ins can be placed in the sidebar or in the footer, you don’t need to use them all. Practice restraint and let your content shine. You or your webmaster will have set you up as an administrator so you will have control of the blog.
So, what to look for in a blog theme? Well, besides an overall effect that you just love, it should have a good navigation with room to expand, sidebar pages and pages with no sidebars [for galleries, etc.], nice category listings, post separation if that is what you want, 2 or 3 columns – and so on. Speaking of sidebars, don’t let it get too cluttered, you don’t really need a list of your pages in the sidebar if you already have a menu bar at the top, do you? Use common sense, declutter and don’t be afraid of white space. More and more I find myself using the 20/10 theme with a nice background. I have changed the theme this week, to the 20/10 as an example and will change it again so that you can see how easy it is. Of course, you don’t want to go crazy, especially if you are branding yourself and your blog matches your website. Then, you might just want a seasonal change. Check the online blog to see the changes. You may also view some custom blogs from the links in the sidebar.
You will notice I have also installed the Share This plug-in which goes at the end of each and every post so that you may Share on Facebook and/or Twitter, or send to a friend in an email.