Photo by F_A
Making vanilla frosting from scratch is actually really easy. All you have to do is combine butter, milk, confectioner's sugar and vanilla extract. The key to getting light, fluffy frosting is to make sure that the butter is at the right temperature. It should be soft enough that you can stick your finger in it and it will leave a dent, but not so soft that it is mushy.  When you cream the butter, powdered sugar, and milk together, it will create a smooth, light frosting that is easy to spread with a knife or to pipe onto cupcakes, cakes or other baked goods.
You should also make sure to use a high-quality vanilla extract. The vanilla has to taste good enough to stand on its own since it is the only flavoring that is being added.
A good basic recipe for vanilla frosting starts with the following ingredients: 
- 2 cups of powdered sugar
- 2 tablespoons of softened butter
- 2 tablespoons of milk
- 2 teaspoons of vanilla
Start by creaming the butter in a stand mixer or with a hand mixer. Sift the powdered sugar to remove any lumps so that your frosting is nice and smooth. Slowly add in the sugar and milk, blending until smooth and fluffy. Finish by mixing in the vanilla flavoring.
Here's a great video that shows the process from start to finish: