Toolbar Buttons have Menus: Almost all the toolbar buttons have right-click menus providing handy access to a number of contextual commands.

Try the Mini Tree: Try out the Mini Tree for 10 minutes. Chances are you never go back to the normal folder tree.

Go Up by Double-Click: Double-Click the empty space in Tree or List to go up one level.

Mouse Down Blow Up: If you ever work with images, be it photos, web graphics, or whatever you must try out Mouse Down Blow Up. And note that thumbnails support a Transparency Grid.

On-the-fly Font Sizing: Use Ctrl+Wheel to quickly change the application's font size. The font size is instantly adjusted for all major interface elements. The current value is shown in the Status Bar.

Info Panel Sizing: Enlarge the Info Panel (F12) by dragging the splitter right below the Status Bar. Previewed images are resized in real time.

Here's the splitter.

Locked Tabs: If you work with locked tabs (which you should) then declare one tab in each pane as "Default Tab". This will save you from ending up with too many tabs.

Icon Overlays: To show Subversion/TortoiseSVN icon overlays in Tree and List simply tick "Show Icon Overlays" in Configuration | Advanced.

Time Stamping: Time Stamping (modifying the timestamps) and Attribute Stamping (modifying the attributes) of one or more files can be done directly on the Info Panel's Properties Tab.