Let the brisket rest before slicing
Identify the grain direction
Separate the point and flat if needed
Slice the flat against the grain
Slice the point against the grain
Use a sharp slicing knife
Cut thin slices for the flat
Cut slightly thicker slices for the point
Keep slices even in thickness
Stop and recheck grain direction as it changes
Slice only what you need to serve
Cover the remaining brisket to keep it warm