This page will show you how to make your very own nerf ropedart to train with.
A few things you will need.
A length of rope, proportionate to your finger tip to finger tip wing span... times 3.
(I am a little over 5'½ tall thus, I would want to start with a length of rope roughly 15'-18'.I recommend .550 Para. cord. Which is plenty strong enough, and very reliable. As well as being what we used for this demonstration.)
You will also need a woven style hacky sack.
Left to right: Front (note: the spiral) and Back (note: the jumbled knot)
A handy pair of scissors.
A crochet needle or chopstick or shank of roughly the same diameter.
(Note: a Swiss army pocket knife works great!)
A Lighter (source or flame)