Throwing is the single biggest differentiator in DDC. Being able to not only throw in consistently but to make effective throws for a variety of situations is crucial to success.
Sidearm meets baseball. The crucial action is in the snap. Most beginners will snap their wrist the same way they would a ball, resulting in a fluttery mess that flops over to the side before dying ignominiously short of the court. The proper snap for any sidearm, including a hammer, is one where the plane of the hand stays aligned with the plane of the wrist. One way to visualize it is by holding your hand out as if you're going to shake someone's hand (both of you are, of course, fully vaxxed). Point your fingers down, as if your hand were a knife slicing cake. That will keep the disc in plane as you release it, allowing it to retain its velocity. Practice the motion until you can throw the disc with little or no flutter. You should be able to throw one that comes out of your hand vertical, then lands and rolls. If you're still getting a lot of flutter, try slowing down your arm and speeding up your wrist.
Once you can get it consistently into the court, you'll find that the two-finger has a lot of applications. It can be used as a serve, lead, rally, or attack shot. In high-level play, it's most often seen as a burn. Right-handed players without a lefty or sidearm may use it for serves, leads, and rally shots when the wind is from the right. Since a two-finger burn tends to roll in a donut to the left, the front right corner of the opposing court is called the "strong side". It's much easier to get a burn to land and stay in over there. The left side is called the "offside". To get that to stay requires good control of the landing angle, as the disc will need to land close to flat. One way to vary the landing angle is by changing your arm angle. The lower you drop your arm (toward a sidearm throw), the more the disc will roll. To throw an offside, raise your arm a bit. You can also change your snap subtly (toward the baseball release described above) to add a bit of flutter. I've found that a small amount of flutter helps consistency, even though it takes a bit of velocity off.
These are throws that are good to have in your arsenal. The wrist flip is a primarily defensive throw; any solid front will have one.
All the same principles described above for throwing a two-finger apply to the sidearm. The snap needs to happen in a flat plane, so that your palm and wrist are facing up when you release the disc. For a flat sidearm, you can visualize the snap like scooping water out of a sink. You'll need to experiment to find the timing. Be careful not to use too much arm, and try to get your elbow to lead the throw. To do that, you'll need to bend it and keep it fairly close to your body throughout the throw. To throw it with hyzer, bend at the waist and lower the disc. If I need to make sure I get enough angle on the disc I'll even lift my left foot off the ground, a stance I call the "flamingo".
The wrist flip has one real purpose: a quick off when you've caught an upside-down disc in your throwing hand with your thumb in the rim and your fingers on the flight plate. That is both the normal way to catch an upside-down disc below your waist and to your right, and the exact grip for a wrist flip. To get rid of it, all you need to do is turn it over and throw it. The arm motion is very similar to that of a sidearm, but with the elbow trailing. You still need to bend your elbow to get any punch on the disc.
A scoober (outside of ultimate at least) is an upside-down throw from a backhand grip with the disc held above the shoulder and the flight plate facing outside. The flight path is the inverse of the hammer's, so the strong side is the opposite as well. That's the main reason it can be useful - it's a bonus to be able to hit either corner with a strong-side throw. However, only a few people have been able to throw it consistently well. It has always eluded me and is the reason I have a lot more experience with the next throw.
Like the scoober, the strong side for a staker is the left corner (for a right-handed thrower). The grip is a bit odd: the thumb faces forward and goes under the rim, and the index and middle fingers anchor it on the top and rim. The throwing motion is essentially that of a backhand. To get it to land in the court, throw it like a backhand roller, and pull it from low to high since the disc tends to dive a bit and will land short otherwise. You'll also likely need to roll your wrist over a bit on release to get it to turn over enough not to roll. It's not an easy throw to learn, but it might be easier than learning a lefty two-finger burn.
This is another throw that is difficult to learn and master, as it's very unforgiving of mistakes. The grip is basically that of a wrist flip, with the thumb in the rim, and the throwing motion is backhand. Everyone's first (and maybe hundredth) attempts will "turn under" - the nose and/or right side of the disc will ride up, and the throw will end up short and/or left of its intended location. To avoid that:
Once you have it, you can annoy the opposing back by throwing high UD leads.
If you feel your thumb is being underutilized, read on. The following throws are not often seen in competition.
This is held with the outside of the thumb against the inner rim, with the index and middle fingers providing support. The flight plate faces out, so the flight is similar to that of a scoober (making the left corner the strong side). It's difficult to throw without flutter - an abbreviated arm motion with lots of snap helps with that.
The entire thumb rests against the inner rim, with the flight plate on the inside, making the flight and strong side similar to that of a two-finger.
These are mostly novelty throws. The only one you'll see in competition is the first one, and even then only a few times a year.
A low-spin wrist flip, thrown with a locked wrist. Ideally it has just enough spin to fly like a regular throw, then at some point when it's over the opponents' court it loses stability and flies unpredictably. It's DDC's version of a knuckleball. It's not easy to throw a good one. The bad ones fly like a slow fluttery two-finger and are easy to play. The fact that it's difficult to throw the nasty one makes me think how fortunate it is that in baseball it's hard to throw a good knuckleball. If it were easy, it would dominate the sport to an undesirable degree.
Essentially a backhand thrown with a two-finger grip, with the flight plate toward the body. Because this throw doesn't make much sense, it flutters a lot.
True esoterica. Put all four fingertips inside the rim and let the disc dangle, then with a motion similar to a wrist-flip fling the disc toward the other court. Add a modicum of spin. If you're lucky, it'll start out flying vertically and then shudder into a hyzer.