Any tips on doing everything by hand? (Sans mixer)

Just elbow grease really. For years, I made cakes like this one by hand. Just about six months ago I acquired a handheld electric mixer. It's kind of therapeutic doing it manually though and you can often feel how the texture changes.

Recipes for cakes like these mostly predate kitchen appliances (sometimes by centuries) and thermostatically controlled ovens. If you read Pellegrino Artusi's classic 19th century Italian cookbook, when he writes "mix" he means by hand because there were no electric mixers in Italian household kitchens in 1895. And oven temperatures are hot, medium, and cool (back then the cook was chucking firewood into the oven so there was always some temperature variation).

If you are mixing in a metal bowl, put down a damp towel onto the counter, it'll help minimize the bowl from sliding around. If your arms get tired from the exercise, enlist help from others.

Best of luck.