Here's how you can install Classic Theme Restorer for Firefox 29. Classic Theme Restorer will let you make Firefox 29 look like Firefox 28.
1. Go to the Classic Theme Restorer site in Firefox 29.
2. Click the Add to Firefox button.
Classic Theme Restorer will have a lot of appeal for Firefox users that don't like Firefox 29, and there seem to be quite a few of them. Firefox 29 brought a lot of interface changes and some of them don't have a lot of appeal.
According to Ghacks:
Classic Theme Restorer is without doubt the major add-on for Firefox to change its look and feel to pre-Australis. Once you install it, you will notice quite a few changes right away.
The Firefox button is displayed again in the interface instead of the Hamburger button, and it behaves exactly like the button that was implemented in Firefox 28 and earlier. Tabs are displayed squared again as well right away, and the add-on has been restored at the bottom of the browser window.More at Ghacks
Additional resources for Firefox