The following technique was a big factor for me personally in developing my game. I doubt it will be anything new for my readers who are experienced ultimate players, but I wrote it up to facilitate sharing it with developing players.
The technique is pretty much what it says in the title: play games with the intention of developing new skills. Here's what I mean by that: before getting on the field, take a minute to choose a skill that you'd like to work on. For example:
"I want to practice my in-game OI backhands"
"I want to practice my lefty scoobers"
"I want to practice having better awareness of when a defender is poaching off of me"
"I want to practice backpedaling quickly to defend against give-and-gos"
etc etc
I'll mostly talk about developing new throws in this article, since throws are easy to talk about, but don't forget there are lots of other skills, too.
Once you've chosen that skill, play pickup with the intention of looking for opportunities to use that skill. Don't worry so much about winning or losing, or even about always making the right pass (unless "making the right pass" is the skill you're working on!).
Taking a skill from the practice field to game situations can often be a big hurdle to clear. We practice and practice a new skill, but when we're in the heat of the moment we go right back to doing the same old stuff we're used to. This is my technique to help myself get over that hurdle. Instead of jumping straight to a "real" game situation, I create this quasi-game situation, where there's a game happening, but mentally I'm in a different state than I am when I'm playing to win. My mental focus is on development, not winning.
In between points, check in with yourself:
Did you use the skill?
If you used it, how did it go? (And what does that say about how you've been practicing this skill? Do you need to practice differently based on how it actually gets used in games?)
Was there an opportunity in retrospect to use the skill but you didn't think to try it?
That last bullet point was a phenomenon I regularly experienced. Only in retrospect did I realize I missed a chance to use my skill in the game. But this sort of after-the-fact-mindfulness, in my opinion, was an important first step to actually noticing the opportunities in real time. The reminder that I'm looking for opportunities strengthens the concept in my mind, making it more "mentally available" in future game situations.
Usually I'd just do this mental check-in between points. But I've experimented with written check-ins as well. There were times I tried to write in a journal on my phone when I was resting between points, although that never went as well as I hoped (apparently I needed more meta-intention). I was more consistent about doing a little mindfulness journaling at home on my computer after a game.
If you've got a friend who's willing to help out, setting up a "motivation buddy" system could be another way to implement this "mindfulness". Sometimes it's easier to notice what other people are doing than to notice what we ourselves are doing.
Some skills can be worked on all the time. Don't feel good about your OI forehands yet? Every forehand you throw upfield against a force-forehand mark could be an OI! Practicing a low release, big step-out backhand? There's no reason you couldn't just do that on every single dump throw.
If you need to work on your forehand blades, they can be dump throws, they can be breakside throws, and they can be your go-to way of getting the disc up the field on the open side. You'd be surprised how many opportunities you can find if you don't shy away from looking for them.
In other words, playing should often be an experiment. Try something new, note how it works, and repeat incessantly. Successfully developing new skills is often less about how hard you're willing to work, and more about how willing you are to experiment. But if you can, do both!
Using a new skill in-game will feel awkward at first, even if you've been working on it outside of game situations. But with time it'll feel more natural, and you'll eventually be able to use it in the right moments without needing to devote your mental energy to remembering to practice the skill.
This ability to experiment is a big reason why I still play "casual" pickup games. A lot of the club-level players in my town don't come to pickup. I understand the reasons for that but I think pickup is great for giving me more freedom to experiment. I'm developing new throws much quicker than those more-experienced players.
And though I use "pickup" in the title, any game that feels sufficiently low-stakes works for this technique—fall league, certain scrimmages at practice—even if it's not technically "pickup".
If you're playing with people you like and trust, tell them what you're working on. They can help you end up in situations where you have the opportunity to use that skill. If there's players you don't know as well, explaining to them what you're doing can be helpful as well—"hey, I really liked that cut you made, it's just that I'm trying really hard to get better at my throws to the breakside".
Given a recent Reddit thread on pickup etiquette, I should point out that you don't want to look off open teammates very often. Sometimes playing the game and being unselfish has to come before experimenting with new skills. Communicate with your teammates, and, as the top comment on that thread says, read the room.
Honest communication is always helpful— ask one of the veterans, "Hey, would it be appropriate if I really try to work on [X] at our pickup games?" But I find that really strong players often have a lot of love for people who are actively trying to improve. Dudes chucking up questionable throws without the specific intention of growing and developing a new skill—that's what really gets on the nerve of the experienced players.
As a coach who uses something of a "teaching through games" philosophy (like Ian's book here), I sometimes set up games that are essentially imposing this technique on the team. "Let's play mini, but a hammer throw for a goal is worth an extra point" incentivizes players to work on their upside-down throws in game situations.
But the learning scientists are pretty unanimous that learning based on your intrinsic motivation—learning what you want to learn—is more powerful than having lessons imposed on you. So I'm writing this post for the players, not the coaches—choose for yourself a skill you'd like to work on, and work on it.
For more on this topic, check out my older post Balancing individual growth and winning.