There are some things that I wish I had done to my setups before I ever actually set them up. Most have to do with setting up the stand properly.
Assuming you have a wood cabinet there are a number of things I suggest. First is to apply a waterproof sealant to the entire inside. Unfortunately in this hobby it is more likely than not that at some point water will be where it shouldn’t. Hopefully this is just a minor spill or overfill and nothing catastrophic, but when those minor things arise it is nice to have taken a couple basic steps. One thing I found was that my cherry stand was nothing more than cheaper wood with a whole lot of stain on it. Every time it got wet that stain got on everything, especially the towels. If I had sealed the entire inside of the stand it would not have been an issue. I would also run some silicone on the bottom corners inside the stand. This will help keep water from running under the stand where you can’t wipe it up and keep it inside where you can.
I suggest mounting a power strip on the inside of the stand, ideally against the top of the inside if at all possible. This means the outlets all face down so that water cannot run into them. I have my tanks setup with separate power strips for eveything I turn off during a water change like the filters and heater. This means all I have to do is press a button, not pull plugs and plug them back in every water change. It also means that my air pumps and lights stay on during the water change.
Another good idea is to mount a small under-cabinet light inside the stand so that you can have a good light supply while messing with a canister filter or looking for supplies. Mounting it directly above the door and it having an easy to use button is best.
A small hook on the inside of the door is a great place to keep a small hand towel for drying your hands.
Before you fill the tank there is one thing I would do to the aquarium itself, paint the back. Painting the background on an aquarium will make it look a thousand times better. I personally feel that a tank looks a lot better with a solid background, I prefer black but dark blue is good too. The plastic backgrounds inevitably end up with water spots on the glass, they only touch some of the glass so parts looks bright and parts look dark, and start to fall off. I also don’t see the point in putting scenery on the back of the tank, you are creating an environment for fish that are beautiful, interesting, and relaxing. You should be looking at them, not the background. A simple solid background keeps the attention on the fish. Dark backgrounds and substrates not only make fish look better, but a study showed that they actually cause the fish to produce more actual pigment in their skin so they are genuinely more colorful. I have used spray paint, acrylic craft paint, and latex interior paint. The spray paint seems to be the most durable, but is harder to do since you need to setup a whole area for it in a well ventilated area (outside or in an open garage) which some people cannot do. The acrylic and latex paints are easier to apply but not quite as durable. The good thing about the interior latex paint is that you can pick any color you want, so you can have the tank’s background match your walls, furniture, the aquarium stand, anything.
If the tank will be setup in the corner of a room that that the back and one of the sides will be against a wall, paint the side of the tank that will be against the wall too. From the front of the tank you will see the side as colored instead of that mirror effect you usually get when looking at the side of a tank from the front. This looks better than leaving it unpainted.