Properly speaking, there is no such thing as a “lasso.” You may lasso things with lariat, but you cannot carry a “lasso” because lasso is a verb.
The American cowboy learned the use of la riata from the Mexicans, and he shortened the name and called it lariat, which has become the accepted name among Americans. Cowboys call it simply a rope, and when he lassos a steer he says he “roped it.”
Common wisdom of the period (and even today) claimed the very best lariats were made of raw hides. The raw hide is first cut into strips as long as the hide will allow. The hide is half- tanned without removing the hair. The strips are next soaked in water and stretched over a block, after which they are neatly braided into a rope. During the latter process they are carefully pulled as tight as possible. When this is done the rope is buried in the ground and allowed to remain in the earth two weeks to soften, after which it is dug up and again stretched over a block by means of heavy weights. After the hair has been sand-papered off, the rope thoroughly oiled or greased with mutton tallow and properly noosed (with a hondo/honda/hondoo—all depending on which source I looked at for reference, but all pronounced “onda”), it is ready for use.
Learning to throw it is a whole other thing. To do that, start with a noose only a foot or a foot and one-half in diameter, allowing the rope to slip and the noose to grow larger as you swing it. Take your position in front of a target, a post for example. Run the end of the rope through the ring or "honda," as it is called. Coil the rope in your left hand, carefully leaving about six feet of loose rope between the coil and the noose, and see that there are no kinks in the line and that the coils will slip easily off when the noose is thrown. Take hold of the noose with your right hand about a foot from the ring, and with the same hand grasp the rope the same distance below the honda.
Allow your wrist to move easily as you swing the noose over your head from right to left. Let your wrist act as an axle, and swing the rope as if it were a wheel revolving horizontally around your wrist and over your head. When you feel that the proper time has arrived for making the cast, choose the moment as your swinging hand comes around from back to front, take a quick step forward, bring your hand, with palm down, forward and down to the level of your shoulder, let it stretch to a full arm's length without interrupting the swinging motion of the noose, and let it go. Try to keep the noose as level as possible the whole time, also, until you actually let the rope fly. Then, the right side of the loop should be lower than the other so when it hits the post, the opposite side of the loop will flip over the target.
That all sounds easy enough.