I do my own horses feet being they are pretty simple and have the patience to deal with me learning on them. My mom is a certified farrier that turned to natural hoofcare as a better alternative and she taught me some of the fundamentals. I trim them more frequently so it is mostly about rebalancing the hoof than actually taking any length off. When I work on them I use the Hoofjack. Best invention ever. Has an interchangable stand with a craddle that is wonderful and really saves your legs from having to hold them up. I also found that Bellota rasps are my favorite to work with. After I run the rasp over and create a balanced hoof, I do take nippers slightly around the edge of the hoof and rasp at a 45 degree angle to get that nice roll. I use whats called racetrack nippers. They are smaller and easier to manipulate than regular nippers. Then pull it forward and clean up the outside rim. My guy has one hoof that tends to flare so I go a little more aggressive on the outside edge to keep it in check. Pick it up and let it hang naturally to double check to make sure I don't see any high spots and then I like to watch someone walk them out a few steps just to make sure they are landing evenly and call it good. Im sure its more complicated than that but this has worked well for me and my horses.