Some folks might tell you to split your avocado in half, then scoop the meat out of the skin before you slice it. If you want thin, neat, picturesque slices, however, you should do the cutting before you peel. Photo by Isha Zubeidi.
As Sarah Jampel at Food52 explains, scooping before you slice will often leave you with dented and mashed slices. It's also easy to leave a lot of flesh clinging to the skin if you don't scoop carefully. To avoid that, Jampel recommends you split the avocado in half like normal, then slice before you peel. Lay the avocado half flat on your cutting surface, flesh side down, slice as thin as you like, then carefully peel the avocado skin from each slice. This makes the cutting process a little safer too, since you won't be trying to grasp the slippery flesh of the avocado.