Here is the perfect way to prepare this most divine of foods:

First, get rid of your measuring cups and so forth. You don't need them. They're not necessary. The only hardware necessary is a stove, a medium-sized pot with a handle, a wooden spoon, and a fork.
Step One: Fill the pot about 2/3rds full with water, and bring to a full, rolling boil. I recommend that you use on of the smaller coils on the stove, and that you set it to its hottest setting.
Step Two: Add the macaroni and set a timer for 7 minutes, no more! Make sure you remove the cheese pouch from the box before. Turn down the heat on the stove a little bit. Not much, mind you. The key is to keep the water boiling. After about 30 seconds, stir the macaroni to separate it, and also scrape along the bottom of the pot to prevent stickage.
Step Three: Relax. Read a book. Watch TV. Urinate. You may also stir the macaroni if you wish, but if you have the oven setting up high enough, it will keep the macaroni moving and there will be zero clumpage.
Step Four: When the timer goes off, drain the water. Use the lid, use a collander. Whatever. Next take 1/2 of a stick of butter and stir it into the macaroni. The best way to do this is to stick the fork into the butter. It should make a satisfying squishing sound as you force it around the macaroni. I suggest adding the cheese powder shortly after the butter. The extra lubrication and still large size of the butter stick facilitates the sometimes tedious process of mixing in the powder. Notice that no milk is involved. The easiest way to ruin a great batch of mac & cheese is to add too much milk. With this much butter, it isn't necessary anyway. Also, do not add 3rd party foodstuffs like cut-up hotdogs. That's gross.
Step Five: Eat the mac & cheese straight from the pot with the wooden spoon. This is important for the ambiance, and I recommend watching Fox simultaneously.

If you have done everything correctly, your mac & cheese will be the thickest, creamiest, and tastiest mac & cheese ever.

N.B. - This applies only to original Kraft macaroni & cheese.