The positioning of the sheep as you shear is important. It's designed to keep the skin taut to avoid cutting it. The order and pattern are different if you are clipping with machine shears, or hand shearing with blades, so remember to watch the relevant you tube clips. We use blades, which are so nice and quiet and you can shear your sheep out in their pasture or under cover as you choose. With clippers you need a power source.
Never pull on the wool, only on the skin, as pulling the wool causes the skin to tent and you can remove a large piece of skin if you cut at that point. I'm never sure how people manage not to cut their sheep when they shear them standing up. Cover the teats, and penis in a male, with one hand as you clip the belly.
The pattern of shearing and moving round the sheep is like a ballet and it takes ages to learn it but once you have then you are free of the annual race to find a shearer who can come at the right time and won't charge the earth. If you are using the fleece yourself, or throwing it out, it really doesn't matter whether or not you get it off in one piece or in lots of little bits. Once you get good, you can enter some fleeces at your local show. Good luck