To get the perfect sponginess in the cake every time. You need to focus on combining the mixture together nicely.
Keep the elements at room temperature this is the biggest hack of baking. It makes the mixing part easier.
Having an understanding is good but do not rely on the gut feeling. While baking make sure to read the recipe properly at least once.
To get the perfect batter for the cake. Make sure you have mixed all the components well.
Make your cake more fluffy and spongy by adding buttermilk into it along with some baking soda.
Do not overmix the batter because it will create many bubbles in your cake batter. This can lead to make the cake more dense.
Patience is the key. You might end up baking dense and dry cake but if you have patience you will get the trick.