Prusik is a great knot. Ive used it on a tree and even smooth poles as an anchor point for a hammock. But it needs a load to remain secure (Roger Moore 007 fashioned his shoe laces into prusik knots to climb a thick rope to a monetary on a mountain peak).
I use ropes to lash everything down, because straps with ratchets can apply too much pressure. My tie down ropes are 1/2 inch braided, which is overly strong, easy to tie and untie, and it abraids less on things I lash down.
Anyone unfamiliar with knots can find details on YouTube. A loop like the “Alpine Butterfly” (or any of various name for it) can be used instead of the taut-line, which can slip slightly. The “Alpine Butterfly” won’t slip, the wrap puts less stress on the rope, and its easy to untie. Once the working end of the rope passes through a cleat or around the object securing the load, pass the end through the loop in the rope and it serves as a pully to increase tension. Then go about wrapping the excess around the rope and tie it off.
Constrictor knots (similar to a clove hitch) are useful. I use one to secure both ends of a length of 1/4 inch by 5 feet rope to a hiking stick. It doesn’t slip, but can be slid to pull it taunt or give it slack so it serves as a “rifle sling” to free up my hands. Then it can serve as a tarp pole with a loop on one end fastened to the tarp with stick toggle, and another length of rope fsstened by a “sheet bend.” I can’t find directions for the specific constrictor knot, but can take a picture and post it for anyone who wants to copy it. I used the thin nylon venetian blind cord to make an eyeglass lanyard when I couldn’t find my store-bought lanyard. A constrictor knot on the earpiece arms is neat and holds tight. To hold the glasses tight on your head, use twist ties to cinch the lanyard (plastic is better than the paper coated ones that dissolve when wet, or use zip ties, another piece of cord made onto a constrictor). Pull the little zip tie back and forth to tighten the eyeglasses to fit your face.
There are knots for virtually everything.
