Knowing the three basic mixing methods will make baking easier. You will be able to assess a recipe and anticipate the next step.
Creaming method
The creaming method is used for cakes and many cookies. The fat is at room temperature and beat with the sugar until light and fluffy. The room temperature eggs are beat in one at a time.
The dry ingredients are sifted together and the liquid ingredients are combined separately. Then alternately the dry ingredients and liquid ingredients are added to the butter and egg mixture.
This method yields a tender crumb and lighter texture from beating air into the butter and eggs. Often with cookies you will lower the speed of the mixer in order not to beat air into the eggs.
Examples
Muffin method
The muffin method is used for traditional muffins and for brownies. The fat is melted and the eggs are beaten lightly and are then combined with any other liquid ingredients before stirring in the dry ingredients.
This is the simplest method yielding a denser product with a larger crumb.
Examples
Muffins are the eponymous example only I prefer muffins made using the creaming method.
Biscuit method
The biscuit method is used for biscuits and scones. The fat is very cold and cut into small cubes. The dry ingredients are combined including the sugar then the butter is cut or rubbed into the dry ingredients with a pastry blender or your fingers. The eggs are beaten lightly and mixed with the other liquid ingredients before being stirred in.
This method yields a flaky texture. Think of rubbing the butter into the flour to form little sheets adding to the flakiness.