Opinions vary about how to prepare asparagus for cooking. Unless you buy spears that have already been trimmed to the top four or five inches, you’ll need to remove the tough ends. Some people simply cut the spears where the green color fades, but I prefer to snap off the ends. I hold each spear, one at a time, in both hands and bend it until it breaks naturally at the point at which it becomes tough. I think this is a more reliable trimming method, and I don’t mind that the snapped spears aren’t all exactly the same length.
Many cooks peel asparagus, especially large spears, but I never do. If you’ve snapped it properly, the entire spear will be tender, so peeling doesn’t enhance tenderness — it just removes flavor.