Professional bakers generally weigh ingredients but I don’t consider that practical so I do what I think most of us do, which is use measuring cups and spoons. Measuring liquids is pretty simple and requires a glass or plastic cup with markings that should be viewed at eye level, but dry ingredients are where recipes are affected the most. The proper way to measure flour is to first stir the flour in its container in case it has settled too much and become compacted. Then you are supposed to spoon it into your dry (stackable) measuring cup. Since I bake so much I keep my flour in a covered container but I always stir it first before measuring. My method is “dip and level” meaning that after I stir the flour around in the container, I dip my measuring cup into the flour, do not tap or shake the cup, and then I level off the top with a knife. I dip and level with sugar also but it does not tend to settle as much as flour. With small dry ingredients like spices, baking powder, etc. I just dip in the measuring spoon, scoop it up and then level off with a knife. I think most failures in baking happen by not stirring and aerating the flour first.
Here’s some advice I have based on some mistakes I have made:
1) Never measure liquid things like vanilla or oil in a measuring spoon over the bowl you’re working in – it can easily spill over into your bowl and there’s no way to fix it.
2) Never break an egg directly into a batter but always into a small bowl or cup first. You’d be surprised how often you’ll find a piece of egg shell.
3) When baking with cocoa powder sift it together with the other dry ingredients because it’s not always easy to incorporate it later.
I also found a couple of helpful links below…