Well, controlling the center is a general guideline, not a requirement. You can be completely winning while supposedly your opponent has complete control of the center.
How am I supposed to "control the center" when trying to control the center is losing?

I've complained about my atrocious skill in multiple circles of mine and the most common tip they've given me is "control the center." As in "get pieces on those four squares at the center of the board."
Okay... but my opponent is also trying to do it, too. And when I try to take territory in the center, I'm losing. My pieces are either hanging or sparsely defended. I'm never in a good defensive position while trying to "control the center." What am I supposed to do?
For me it is like soccer, ofc you want to control the center at football/soccer >50% of possession/control. But it is not a requirement to play good possession/control , there are other tactics like defensive setup and etc. The idea is to play the best that you can play. Even hanging pieces can be useful if you can maintain tempo. You might need to win in defensive territory instead of the center.

I've complained about my atrocious skill in multiple circles of mine and the most common tip they've given me is "control the center." As in "get pieces on those four squares at the center of the board."
Okay... but my opponent is also trying to do it, too. And when I try to take territory in the center, I'm losing. My pieces are either hanging or sparsely defended. I'm never in a good defensive position while trying to "control the center." What am I supposed to do?
Sometimes it helps me to not only try to directly control the center four squares, but the squares surrounding it, covering more area to make it hard for the opponent to open up attacks on me.

You put pieces in the middle but you also need to defend your pieces
This is a very theoretical position but it should show an extreme example of space advantages

occupation helps only when the pieces occupying the center are also controlling it
basically, occupation is a part of control


Controlling the center doesn't mean occupying it with your pieces, it means having influence over those squares. It's also important to not get so focused on controlling the center that you lag behind in things like development. I looked at a few of your games and it seems like you just move pieces kind of randomly/arbitrarily after move 4.

All I can say is that the more we teach a "good position" as a general rule of thumb, the more rules we will produce on how to exploit it. Good will then not be good.
I've been taught that using the center of the board is the best. The center tends also to be the most open and available area on the board, making it the easiest to attack. All of the sudden, no longer is the center a good idea.
The first thing you should do is stop being so critical of yourself. The second thing would probably be to work through the lessons on this website.


When I was first starting out I used to try to dominate the center with my pawns, but after a while we learn to control the center of the board from afar with major pieces.

each approach (classical & hypermodern) to the problem of the center are valid & a universal player embraces them both as such. 🙂
You don't put pieces in the center to control it, you do that if you control it. Otherwise you just drop material. Sometimes, of course, putting a piece in the center may also help controlling it. That is the reason why pushing the central Pawns is so strong. They not only attack central squares there, they also create space to be used by pieces in order to control the center.

Eh... puzzles are nice to figure out but I don't see how I can use them for my advantage.

Controlling the center doesn't mean occupying it with your pieces, it means having influence over those squares. It's also important to not get so focused on controlling the center that you lag behind in things like development. I looked at a few of your games and it seems like you just move pieces kind of randomly/arbitrarily after move 4.
It's honestly because I don't even know what to do next. I'm told to develop pieces as much as I can, but then after that I can't think that far ahead.

The first thing you should do is stop being so critical of yourself. The second thing would probably be to work through the lessons on this website.
I am trying to use lessons but, as a free account, I'm restricted to one a week.

You don't put pieces in the center to control it, you do that if you control it. Otherwise you just drop material. Sometimes, of course, putting a piece in the center may also help controlling it. That is the reason why pushing the central Pawns is so strong. They not only attack central squares there, they also create space to be used by pieces in order to control the center.
I'm... lost on this one.

see if you can get somebody to gift you a month's worth of diamond ($13) so you can check it out... i've done 1,000 lessons & they're all excellent.

your pawns create space behind their advance almost like an advancing fence.
they also help to prevent the opponent's activity by restricting their movements (because the opponent doesn't want to trade their pieces for your pawns, they have to run away from your pawns' attacks).
your pieces (when it's possible to safely go there), can use the 4 center squares, and to a lesser extent the surrounding squares, like a launching pad. you can attack the enemy queenside, center or kingside from the center, whereas if you launch a flank attack you're more limited.
really the best way to play at your level is just to stay solid & active & take the opponent's pieces when they mess up:
after you win one for free, start trading pieces for your opponent's equal pieces.
once you're the only one with pieces, start taking your opponent's pawns.
once their pawns are all gone, start pushing your own pawns.
make a few queens & checkmate the enemy king.
remember these values at all times:
pawn = 1
N & B = 3
Rs are = 5
your Q = 9.
Do not control the center. Go for the big 4 moves.
Not helpful, unlike the rest of the great advice here. What are these "big 4 moves?"
As black you have options to develop pawns to 1..d5 1..e5 1..d6 1..e6. Maybe as white you don't need to employ those moves because you can easily control center with white pieces/pawns.