Properly baked cakes should be evenly brown, shrinking slightly away from the sides of the tin and firm when touched with the fingers. A fine hot skewer inserted into the centre of a non-fruited cake should come out clean.

Fruit cakes 

A slightly bubbling sound indicates that further baking is required.

Sponges 

These should shrink slightly from the tin. When pressed with a finger a sponge should spring back leaving no impression.