When they say beat the sugar and eggs for several minutes- do it! It makes a huge difference. Remember the creaming video from our first week's baking challenge? If not- watch it here. You really can't underestimate what adding air to your mixture does to you overall product!
Prepare the pan the way it calls for. It makes your finished brownies where you can perfectly cut them without them falling apart.
Something I often stress to my students that is so important that beginning bakers don't realize, is placement of the baked product in your oven. It is so important that you are baking exactly in the middle of your oven. When you are more towards the bottom, your bottom edges will burn and the tops will still be raw. Too close to the top of your oven, your tops will be burned. The way most residential ovens work (I say most, because some of yall might have residential convection ovens- that is a separate bullet here) is that hot air rises from the bottom of your oven. Think of having a two story house- the hot air is rising to the second floor of your house. So in your oven, your sweet spot is that very center. It is also important that you get your brownies in the center horizontal wise.
If your oven is convection (if it is a switch that you can turn on convection- I suggest keeping it at a regular conventional oven) and convection only- lower the temperature to 325°F and bake for the first time 18 minutes and the second time 16-18 minutes. The air movement does cause the baked good to bake faster, but every oven varies so much. I know it's crazy to say, but if you bake enough, you get to know your own oven and what to expect.
Cooling is another big step people often skip. This is soooo very important. What you are allowing to happen is for the fats that are liquid when heated to re-solidify as the cool (ever try to eat a cookie made with butter right out of the oven and it disintegrated into nothing, but after waiting 3-5 minutes its the perfect solid consistency... the butter was melted right out of the oven, and more of a softened state in the second part of the scenario). In my culinary class we have cooling racks, I don't have the space for one at home. So what I do is I take two of those yeti style metal cups that are the same size and flip them over. I then put my cookie sheet/cake pan on top of that. What this does is it allows air flow all around the product which disperses the heat. (Metal cups are crucial here... you can't use plastic as plastic melts... please don't make that mistake).
In the video/recipe directions it talks about cleaning your knife between cuts. This is a very important step to keep your brownies perfectly cut. Not cleaning the knife will leave the fudgy residue on the knife which will then stick to your brownies as you cut them and tear them apart. Get a damp paper towel and wipe between each cut.
Another great thing about preparing the pan the way that the video shows... after eating a few brownies, you can take the leftovers and easily slip into a gallon size bag! This keeps the brownies super moist for the next few days..... if they last that long.