Basic (and sub-basic) stuff to know:

• Monitor on/off.  Monitor off saves power and it is easier to hold the camera steady if you are using a viewfinder.
• Removing memory cards and transferring image files.
• Halfway shutter depression to focus.
• Know if you actually took a photo.  (I am serious!!)
• Using the menu.
• VIP: Set JPG compression to the highest quality (or shoot TIFF or RAW for special photos, but this requires significant memory and it is slow).  See File Format page.
• In most cases, shoot at the highest resolution.  (Use lower resolution if you are severely short on memory or if you have a lower end camera that has a very small sensor.)  You can easily resize the images later.
• Flash off, fill flash, and red-eye reduction flash settings.
• Zoom.
• Viewing previous photos.
• Close-up and distant landscape settings.
• It is best not to transfer images directly from the camera to the computer because of wear and tear on the camera components (and battery).  Purchase a $25 card reader and the transfer will also be faster, or use a docking station.
• Do not touch the display monitor or the lens.  (That should be a no-brainer, but many do it.)

• Burst mode for taking 3 or 4 high resolution shots in a second.  (Some cameras don't have this.)
• Movie mode, which yield some limited video.  (Some cameras don't have this.)
• Exposure EV plus-minus exposure changes.
• Expose for the highlights and then adjust the shadows when editing.  This is the opposite of film cameras where you often expose for the shadow and deal with the highlights when printing.
• Timer.
• Read the stinking camera manual and keep it in your camera bag when you travel.  However, beware that some of the manual settings are better to ignore because you can accomplish the same results by editing the image on your computer.
• Learn some things about image composition, lighting and timing.
• Change ISO ("film" speed settings)
• White balance options (this is a bit advanced) are very useful when shooting indoors without a flash.