Sticking cake in prepared pans

I find that baking spray with added flour in with the oil works a little better for me than spraying and adding flour. I think because the oil tends to collect in some places and then you get a lot of flour in that one ridge and not evenly coating the pan. If you use butter or solid shortening that tends to be easier to evenly coat, but the flour is still not going to be as even as with the baking spray, so that might help.

If you're making something like a pound cake (with lots of butter), it is likely to come out of the pan better if you let it fully cool first. If you're making a cake with vegetable oil, I think it comes out of the pan more readily when it has cooled some (about 10 minutes or so) but not completely.

I sometimes run a thin, flimsy plastic knife along the edges to loosen things. I also put a plate on the open part of the pan (what will be the bottom of the cake) so that I am supporting the cake as I turn it over. This works best if the cake rose to fully fill the bundt pan, otherwise the middle ring will cause the cake to be suspended over the plate, which is what I'm trying to avoid. (If you're in this situation, you could roll up a clean kitchen towel or two and make a ring out of it and use that to fill the gap, but you may want to put some parchment or wax paper between the cake and the towel.) I want the cake to be fully supported first by the pan and then by the plate. I can then tap and jiggle the pan and see if it is coming loose, and if it isn't, I can abort and let it cool a little longer.

Another thought, though, is that some cakes hold up better in a bundt form than others. Pound-cake styles work really well for me and show the details of the mold very well. Light and fluffy cakes don't tend to hold themselves together as well to release as well from a highly detailed mold unless you are really careful with the pan prep and temperatures.