There's a lot more to compositing than just getting a perfect cutout. Here are some golden tips by Unmesh Dinda of Piximperfect on how to get a seamless blend.
When first getting started with compositing it's easy to overlook some slight exposure or color differences because, at first, getting the selection spot on takes a lot of practice and trial and error of different techniques. When one wants to progress and bring their A-game to compositing, however, one has to learn how look a bit deeper to really make the image believable. In this video, Dinda does a great job at explaining how to get around some of the trickier problems.
Starting with getting a good selection
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