You can use keyboard shortcuts to navigate around the site.

HotkeyDescription
Q or /Focus search bar
TabInsert first tag suggestion
and Cycle through tag suggestions
EnterInsert selected tag suggestion
and or A and DGo to previous/next image
RGo to random image
SDownload image
T or EAdd tags to image
Ctrl/Command+S(In edit mode) Save changes

Additionally, press shift + the first letter of navigation header names to navigate to them. ("G" for Gallery, "U" for Upload, "T" for Tags, etc.)