Corner tiles are used on external corners to continue the brick look. For internal corners, simply cut the tiles to fit as close together as you can, and point a thin line of mortar to hide the gaps.
Half tiles have 2 uses- if you are creating a bond pattern such as flemish bond, or if you are finishing half way across a wall, i.e false pillars in front of a fire chamber. For the ends of a wall you should cut the full tiles to size.