Preheat the oven to 425F. Line two baking sheets with parchment paper and set aside.
Peel and chop the vegetables. Cut the vegetables into uniform pieces so they cook evenly. Smaller pieces will cook more quickly; larger pieces will take a bit longer to cook. Vegetables like potatoes and beets, which take longer to roast, should be cut slightly smaller than other vegetables if they are being roasted together. I typically cut my root vegetables into 1/2" cubes.
Transfer the vegetables to a large bowl and toss with olive oil, salt, and pepper. The best way to ensure uniformity is to toss the vegetables by hand. Once they are coated, spread them onto a single layer of both baking sheets.
Bake for about 30 minutes, depending on the vegetables you are roasting. Softer vegetables will take closer to 20 minutes whereas some root vegetables might take as long as 40. Bake, checking every 10 minutes until they are slightly blackened and cooked all the way through. They should be easily pierced with a knife.
Remove from heat, transfer to a serving platter. Taste and adjust seasoning and serve.