Here are two ways to do it:

The Quick Method

You can easily backup a single theme file by going to “Appearance > Editor,” clicking the file, and then copying-and-pasting the contents of the theme file you’re editing into a Notepad document. Read more detailed steps here.

The Complete Method

These steps will help you backup your entire theme:

1. Download an FTP program (such as FileZilla) if you don’t have one already.
2. While you’re waiting for that, go to your WordPress admin, and then click on “Appearance.”
3. Under the “Current Theme” header, note the file path that comes after “All of this theme’s files are located in.”
4. Once your FTP program is downloaded, installed, and ready to go, connect to your website by entering in your FTP hostname, username, and password (these should be different from your WordPress username and password). If you don’t know what they are, ask your web host for help.
5. Once you’ve connected to your website, browse to the folder that contains your WordPress installation (again, ask your web host if you need help finding it), and then browse to the folder you noted in step 3.
6. Tell the FTP program to download the entire theme folder to a location on your computer.
7. Once that’s done, check to make sure the FTP program says the files transferred correctly.

When you have the Monotone theme set up on your blog, it will take the first photo attached to each post and place that image prominently at the top, with the post text and comments below.

Simple enough. But what’s unique about this theme is that for each post page, Monotone changes the colors on the page to match the colors in the photo! A very cool method for creating an eye-pleasing visual atmosphere for your photoblog.

Check out the Monotone demo to see it for yourself.

The theme isn’t yet available for download, but should be in a few days.

The themes that come default with WordPress are okay. But if you’re using a theme designed by someone else, you might want to inspect it to make sure.

First go to the “Theme Editor” tab under the Design or Presentation section. You’ll see a list of files — click the files whose names are listed below, and look for these lines of code. (Of course, if any of this code isn’t there, you can always copy/paste it in yourself and click Save.)

1. Header — Does your theme have this important line of code before the </head> closing tag? It’s used by plugins to insert JavaScript, CSS, meta tags, etc. WordPress itself even uses it to insert some header code.

   <?php wp_head(); ?>

2. Sidebar — Although not as commonly used by plugins, it would be good for this code to be found in the “Meta” section of your sidebar:

   <?php wp_meta(); ?>

3. Comments — This should go at the end of your comment form, before the </form> closing tag. It’s critical for the function of some plugins, such as the popular “Subscribe to Comments.”

   <?php do_action('comment_form', $post->ID); ?>

4. Footer — This line of code should be at the bottom of your theme, before the closing </body> tag. It can be used, among other things, to insert JavaScript code or statistical information (spam counters, etc).

   <?php wp_footer(); ?>

Did your theme pass the test?

#7 — Does It Use Header Tags Correctly?

An SEO fine point: see tip #14 from my WordPress SEO post.

#6 — Does it Have Valid Code?

If possible, validate a default setup of the theme. If the theme itself has errors, the designer probably hasn’t taken the greatest care in its development.

#5 — Is It So 1990s?

A theme that uses tables, font tags, excessive inline styles, etc. (as opposed to external style sheets) will bloat the file size of your blog’s pages, increase rendering times, and eat up bandwidth more quickly.

Virtually all of the popular themes should be fine on this point, but it’s some of the more obscure ones you might have to check or ask about.

#4 — Does It Support the Latest WordPress Features?

Check with the theme’s documentation and see if it supports newer WordPress features such as:

• Tags (added in WordPress 2.3)
• Widgets (added in WordPress 2.2)

#3 — Is It Sponsored?

Sponsored themes are usually an SEO no-no. If the theme’s website says something along the lines of “don’t remove the links in the footer,” that should raise a red flag.

#2 — Is It Unique Enough?

If you’re trying to create a visual brand with your blog, then try to avoid using the WordPress Default Theme or another theme that everyone and their dog has seen on some other blog.

Try to find a theme that isn’t used on an excessive amount of blogs, or get a custom theme developed if you’re willing to hire someone.

#1 — Does it Look Good?

It goes without saying that if the theme doesn’t convey a professional image (and if a professional image is important to you), don’t use it, even if it means you have to go with another theme that doesn’t quite do all of the above.

Finding the perfect theme is a bit like shopping: try some out, see what looks best, and have fun with it!