Determine how many triangles you need, and cut appropriate number using scissors.
Stencil letters onto triangles using permanent marker or craft paint and brush. Allow to dry completely.
Arrange triangles into correct order, leaving spaces between if desired.
Lay your twine, ribbon, or thread across entire banner to determine length. Leave at least 12" extra on each side (more is preferable) for hanging, and cut.
Using large needle, thread triangles onto ribbon, twine, or thread, making sure to catch each one along the top edge on each side and in center. Optional: For thicker twine or ribbon, pin onto triangles, then tack them in place using regular needle and thread until secure.
Hang using extra length on each end from hooks or small nails.
Pennants can be made with any type of fabric and cut into any shape.