Sometimes you just don’t want to be the only one putting together interesting set pieces for your players. Thankfully, there are a number of ways to outsource the labors of a GM to your players.
The easiest method is to simply ask your players for suggestions and to inquire as to what kind of set pieces they want to see. However, the Star Wars RPG already has one method built in; Destiny Points. Page 27 in the Edge of the Empire Core Rulebook details many uses for Destiny Points, but we will be focusing on how they can affect the story directly. The book details one use of Destiny Points being the ability to declare a story element on the spot. The examples given are mostly small conveniences; breath masks stowed on the ship when none were declared beforehand, just “happening” to find cover or immediately needed supplies during a mission, etc. These examples may be small, but can be vital in the instances they are implemented. Of course, all such declarations are subject to your approval as GM, but talking out why you approve or deny any given declaration can help avoid causing conflicts with your players as well as establishing a pattern for your players to use to think about other declarations in the future.
Now, if you feel more adventurous, you can take declarations of Destiny to a greater extreme. For example, let’s say that your players are tasked with eliminating/capturing/infiltrating an Imperial factory on a rocky world. You have stated that the factory is overlooking a canyon and one of your players wants to use a Destiny Point to declare that the cliffside just happens to have a small out-of-sight cave leading into a network of tunnels under the factory. Clearly, the party is going to want to use these tunnels to smuggle themselves into the factory and/or smuggle workers out of the factory, but this would be a rather large change in the landscape from what you had in mind. Now, you could talk it over with your players and concede that there is a cave, but that it doesn’t actually lead to any existing tunnels and would most likely be relegated to serving as a good hiding spot. Still useful, but not as grand as the original declaration.
On the other hand, you could agree to the declaration, but warn the players that the tunnels might not be as safe as they want them to be. This allows your players to alter the terrain of both the game environment and the story while establishing a limit/condition on their declaration to balance out its impact. As for what dangers lurk in the tunnels, you could always populate them with predatory creatures, disorienting mazes, and/or environmental hazards like cave-ins. Of course, there is always the risk of the tunnels being discovered by Imperial patrols if the players aren’t careful, take too long, or simply run into a spot of particularly bad luck.
By allowing Destiny Points to be used in a manner like this example, you can make it so your players are involved in shaping the story with more than just their characters and the examples given by the book. This makes the players feel like they have a greater amount of involvement in how things play out and lets you pad out sections of the game that may otherwise have been more mundane.
Using Destiny Points in the intended fashion is also filled with potential. Using the earlier example with the breath masks on the ship, as the GM you can take that small extra fact and expound upon it to a great degree. The biggest question that the GM can use is why are the masks there. It can be mundane as a just in case measure but can also be because the previous owners of the ship were explorers of toxic planets with various dangers and perhaps the masks were not cleaned properly. Or perhaps the hidden breath masks are in a box with something more dangerous that can help the party but also lead to others being after them. The breath masks could be of a higher caliber and be a set of expensive prototypes the party can replicate or sell which draws the attention of the corporation that initially commissioned the masks. This can lead to an entire sub-plot of corporate espionage and someone stealing prototypes and leaving them aboard another ship to divert attention while keeping one for themselves.
Destiny Points are a useful tool with a variety of uses and their ability to allow the party to add to a story is integral to the fun of the game.