Honestly, I rarely do the steps one at a time even beating by hand. Until I got my new oven, I never preheated either.A lot of the recipes are old and were written for people mixing the batters by hand. With the new powerful mixers, there is no need to "add eggs one at a time until well mixed". Other than the creaming part (not even that step sometimes) and beating in the eggs, I add everything else all at once and have been doing so for a very long time.
There is one particular cake recipe that my mother would make by adding all the ingredients other than the topping ingredients into a pan and beat it up with her hand mixer. No one ever complained about how that cake would come out.