COMPOSITION

Set your camera up on the tripod and compose your picture as you wish.Always try to have something in the foreground, a rock, a tree, flowers, a grass covered mound etc. This adds depth to the scene.Let your eye wander around the viewfinder/screen searching for distracting elements(junk).
Whilst composing, remember the Rule of Thirds bit

FOCUS

Some cameras have a setting that will automatically take a focus reading from several points,both near and far.Others require you to select multi focus option (check the manual). Whichever you use, press the shutter halfway to obtain the required focus. Once this is done,switch the auto focus to MANUAL and be careful not to move the focus ring from here on.

EXPOSURE

Your biggest enemy in Landscape photography,is the sky.It can really mess your exposure readings up.Switch youR camera to apeture priority A or AV or similar.Set your apeture to f16 for DSLR of f8 or f11 for compacts and bridge cameras.Now take a reading from grass, or the back of your hand, or a piece of 18% grey card( photography stores) and make a note of the shutter speed.Switch the camera to full manual mode, set the apeture to f16(or f8/11 for non DSLR) and the shutter speed to the reading you obtained previously.Use a remote or the timer (sometime the shutter speed will be very slow)now shoot.

Sounds long winded but its not.REMEMBER NOT TO MOVE THE FOCUS RING ONCE YOU HAVE SET IT.