As an example, let's think about outdoor accent lighting for a tree of average size. If you are highlighting the tree from one side only, I recommend using 1-2 landscape light, spot fixtures. Place each fixture about a foot away from the tree.
To highlight the trunk, select bulbs with a tight, 10° - 15° beam spread. To highlight the tree's branches and foliage, select bulbs with wider "flood" beam spreads. You can even combine different beam spreads to capture the best features of a full tree.
If you have a very large tree and you want it to appear lit from all sides, I would use 3-4 landscaping light fixtures. Remember that these are guidelines. Experiment to determine what treatment works best for your area!
For a statue or other similar type feature, you may want to try a three-point accent lighting technique to control shading and shadows produced from direct lighting, also known as the "Frankenstein Effect".
To do this, a "key light" shines directly onto the subject from the front, at roughly a 45 degree angle from direct center. A second "fill light" also shines onto the feature, but from the opposing 45 degree angle. A third "back light" shines on the subject from behind as well.
Ideally, it is best to have these outdoor accent lights illuminate the subject at an angle 30 degrees from directly overhead. If you can hit that angle, great! If not, then do the best you can.
Like color temperature, you can find the beam spread for a lamp listed on its packaging. Also, you can accomplish this look without consuming a great deal of power. If you select Halogen/Incandescent fixtures, 20 watt lamps will provide ample light output. If you select LED fixtures, 10 watt lamps will work fine.