How do I bake a decent homemade cake without being a pastry chef

Most cakes that turn out well are the ones where you follow the recipe exactly, without trying to improvise as you go. The secret is weighing your ingredients (or at least using the same measurements every time) and keeping your hands off the cake while it's in the oven - opening the door all the time ruins everything.

Start with a simple recipe like chocolate or vanilla cake. Mix the butter with sugar until it's creamy, then add the eggs one by one, then the flour sifted with baking powder. The batter has to be homogeneous but don't mix too much, or it'll get tough. Put it in a well-greased pan or one lined with parchment paper and stick it in a preheated oven. There you go - you don't need to be a baker for this.

Your oven thermometer makes a difference. A lot of people don't realize their oven doesn't heat the way it should, and the cake ends up raw inside or burnt on the outside. If you're unsure, check the cake with a toothpick in the last 10 minutes - if it comes out clean, it's done. As for the frosting, nothing complicated: powdered sugar with a little butter or even just hot chocolate ganache gives a professional look with zero effort.