Train delivery from wide areas and the runs that attack it. Crossers work on carrying into a proper position and picking a target; finishers work on timing the near and far post runs and finishing first time in traffic.
Set two poles wide to mark the delivery zone, two mannequins at the edge of the box and two inside it, with a full goal and keeper. The wide player carries into the zone and delivers; two attackers time runs to the near and far post. Alternate wide deliveries with a central sequence that combines through the edge of the box into a cutback. Keep several balls going so a delivery is always arriving. Rotate crossers and finishers, and run it from both flanks.
Crossing practices tend to become delivery practices. A player stands wide with a pile of balls, hits them in, and somebody in the box heads them back out. The crosser gets a hundred repetitions of a technique he will almost never perform from a standing position, and the attackers get a hundred repetitions of guessing.
Two details here fix that. The first is that the wide player carries into the delivery zone before he crosses. That single change alters the technique completely: the ball is struck while moving, off a stride, with a defender notionally recovering, which is what actually happens in a match. Crossing from a stationary ball is a different skill and it is not the one that transfers.
The second is the mannequins inside the box. Without them a cross floats into an empty area and anybody can finish it, so nobody learns to attack a specific space. With bodies in there the ball has to be delivered into a gap rather than into a general region, and the finisher has to arrive at a moment rather than a place.
Running central combinations into the same box at the same time is what makes it feel like a game rather than a queue. The finishers cannot settle into the rhythm of one type of service, because the next ball might come from the byline or might come as a cutback off a combination at the edge of the box. Being ready for both, and knowing which post to attack for each, is a great deal harder than heading fifty identical crosses.
Save it to your private drills, then change the animation, adjust positions, swap equipment, or drop it into a session block. Or start from a blank pitch and build your own.