Line a sheet pan with aluminum foil. I typically overlap two or three pieces. 

Remove bacon from package and lay it on the foil lined baking sheet. You can place your bacon very close together but try not to overlap. 

Do not preheat your oven. When you have as much bacon as you can fit on your sheet pan, place it in a cold oven and set it for 400 degrees. 

Set a timer for 20 minutes and start checking the bacon. Depending on the type of bacon and thickness, it could take another 5 or more minutes. 

I start checking at 20 minutes and if it's not fully done, I will flip the bacon and put it back in the oven for another 5 minutes or so, checking the doneness every so often.