For basic pan preparation you want to cute a circle of parchment for the bottom of your pan. Check out my way to get a perfectly sized circle for your pans (the outside of a pan isn’t always the best way to go – it’s usually too big)
If want to bake cakes taller than the pans you have (like I do for cake carving) I also add reinforced parchment paper to the outsides. you start with pulling out a long strip of parchment paper, long enough to wrap around the cake pan.
Then I fold it into thirds, fold up the bottom. Then fold down the top. To prepare it for the pan, I curl it. Then put it into the pan and let it uncurl. I spray a bit of PAM onto the bottom corners of the pan, it holds in the bottom circle and sides of the pan.
All ready for batter! I like to pour the batter up the sides of the real pan, in this case a 3 inch tall pan. Then as it bakes it rises up taller. It’s nice for the carving I do. But you can also cut off the top and cut it into 2-4 layers, fill it and create an extra tall cake (I like my wedding cake layers to be taller, more elegant).