One thing I always do when taking portraits is shoot tethered, and while that used to be with my camera connected to my MacBook Pro, it had changed to my iPad because it's way more portable and convenient. I use the Capture One app for tethering, which works incredibly well: open the app, plug in your camera, or connect wirelessly, and you're up and running. The only problem is that out of the box the iPad screen is too contrasty; it's set up to give the richest colours and deepest blacks for apps, movies, games and looking at pictures, which isn't ideal for tethering. My 6th generation 12.9-inch iPad Pro has Reference Mode, and in this video I go step by step through calibrating the screen for the best results when tethering, editing and viewing photographs.