That's a very general question and difficult to answer in short.
Knife skills. Jaimie on Youtube. Some others as well. The left hand is most important as you cannot easily cut your right hand (you can always try).
Sauté technique. Put a pan on medium heat and leave it there. If you put it on high it might burn. After some minutes, splash a drop of water in the pan (one drop). You should hear it evaporate. Put the heat on high. Put a dash of fat in the pan (oil, butter, grease, you name it). Swirl the pan around a bit. When you see 'waves' on the oil, it's hot. Go and sauté.
If your product is too big or thick for sautéing, go ahead and sauté anyway. Once it's nice on the outside, put some cold liquid in (water, wine, brandy, whatever). Put the heat on low. Put a lid on. Wait.
With these three lessons learned, you can do most basic cooking.
Edit Boil, Simmer & Poach.
Rolling Boil. Used for cooking spaghetti and other pasta, and almost nothing else.
Simmer. Just under a boil (94ºC) used for cooking. Rice, meat, whatnot. It's what you do in step 3 of the above list.
Poach. Very delicate items like eggs can be poached.