You can use heat-proof fabric strips, pre-made "cake strips," or a wet tea towel wrapped around the pan. This ensures consistent results and a perfect cake shape.
A domed cake results from cold batter in a cold metal pan that's placed in a hot oven. The cake will heat unevenly since the middle will take a longer time to rise.
Wrapping the pan in strips of soaked material is the easiest way to avoid uneven layers, and any fabric that's not pre-treated or made from synthetic materials will work.