When it comes to measuring flour there really is not one correct way. You will generally want to use the technique the recipe creator used at least until you get a feel for a recipe. I usually do not weigh my flour but I do when that is how the recipe calls for the flour to be measured. Weighing flour is definitely the most accurate way to measure it but I find that many home cooks do not have a scale. I also feel it is easy enough to measure flour pretty consistently without one, it just requires a couple very simple precautions. Consistency is the important thing here. When using my recipes, unless stated otherwise, this is the technique that I will have used and therefor is the technique that is best to use, at least for the first time or so, until you can convert the measurement into your own preferred method.
It is really quite simple. Flour packs very easily so if you simply scoop a measuring cup into the flour and lift it out you will have compacted the flour so much that you may have as much as 25% to 40% more flour than the recipe will have called for. This is why many recipes will call for the flour to be sifted into the measuring cup, so that it falls in loosely and lightly. That is the important thing, to fill the cup as gently as possible to avoid compaction. You may use a sifter and it will work for my recipes but I take a simpler approach. Simply use a spoon or another measuring cup, scoop out some flour, and gently sprinkle it into the measuring cup that you actually intend to use to measure the flour. Overflow the measuring cup just a little over the rim (not too much or the weight of all that extra flour will compact the flour inside the cup). Immediatly, using a straight edge like the back of a knife level off the measuring cup. Do this right away because leaving the flour in the measuring cup with the extra flour on top will cause it to settle and compress after only a few seconds. Using this simple method will ensure that you do not over measure your flour when using my recipes. Remember, however, that not all recipes requiring flour must be measured exactly. I will mention when it is necessary to be exact with your measurements or not.