I've been playing Star Wars for years, and I've been all over the map, adventure-wise. One of the most frequently asked questions I get is "Where to you come up with such cool game ideas". Well, actually I don't get asked that question all that much - but if someone were to ask, here's what I'd say. . .
Rule one:
The Last Action Hero -
Keep it moving. Speeder chases, raging gun battles, leaps from rooftop to rooftop while perused by the Empire's sinister agents - it's all-good. The point here is to get the adrenaline pumping, instead of letting folks plan out every single move. This is not a war game simulation.
Rule two:
Keep it simple, stupid -
Sometimes the best solution is the simple one. Take the players on a dungeon crawl. (an old D&D term, where every inch of the dungeon was mapped out, and bad guys were lurking behind every turn - for no good reason other than to provide someone for the players to open up some whup ass on). Or, perhaps a simple "Keep the MacGuffin" out the hands of the bad guys" plot - with the players doing everything they can to stay one step ahead of the bad guys.
Rule three:
Brazen theft is your friend (part two) -
Hollywood has been getting mileage out of Shakespeare work for years - there's no reason you shouldn't either. Just watched a cool spaghetti western? Simple file off the serial numbers and use it as a game. How about that Tolken guy - he's done a story or two from what I hear. Books, animation, movies, video games, TV shows - steal from them all. Creativity is simply covering up your sources deep enough to remain undetected.
Seek out real world inspiration - from legends (like the lost ark of the covenant) to modern (the 'who shot Kennedy' cover-up) to modern (the WTO riots in Seattle), inspiration is all around you, ready for the picking. Mix and match events in your local political arena, add in a dash of corrupt imperial influence, and let the players sort out things and put things right.
But inspiration doesn't have to stop there - don't be afraid to borrow floor plans and deck plans like a kleptomaniac fiend. Traveler, Shadow Run, AD&D - even the local supermarket can get into the act. Players will do bizarre things and having a visual representation of where things are will go a long way. Same goes for maps. Travel guides available from your local library are great fodder for this - and can even supply "local color" commentary, as well.
Rule four:
Size does matter -
Star Wars is epic. Big, huge, grand - wide screen panorama THX Dolby digital with a cherry on top. Make your games the same way. Why steal a shuttle, when you can steal a capital ship. Why assassinate a Grand Moff when you can blow up his garrison? Why get involved with merely a outer-rim trade dispute when you can set in motion the very downfall of the entire Galactic Republic? Give the players a game with the odds stacked against them, and they will remember it for a long time.
Rule five:
The 'WOW' button -
Flashback - May, 1977: The Tantive IV swoops in overhead, and everyone in the audience goes "OOOOH! Cool!" Then the Star Destroyer shows up, and suddenly everyone drops a load in their pants.
Make your players drop a load.
Come up with exotic methane planets, flying cities populated with obstreperous hawkmen, panoramic sunsets of purple and red against a massive city skyline. Strange, enigmatic aliens in encounter suits, and eight-inch tall hyper-sentient bug salesmen. You have an unlimited special effects budget - use it!
Rule six:
Don't sweat the details -
There is a lot to be said for making the universe a believable place - NPC's that act and react appropriately, settings that are fleshed out and make the game seem real, and so on - but there is a lot to be said for knowing when to move on. When the stormtroopers attack, don't get bogged down in the details about platoon distribution, sounds and smells and what underwear the players have on. Unless it's important to the moment at hand, move on with things.
In the movies, the battle of Naboo starts out slow, with long establishing shots of the AAT's coming over the hill. Quickly however the battle degenerates into rapid edits, quick cut aways and close-ups. The extra information is no longer needed, so it isn't supplied anymore. You should strive to emulate that pacing.
Rule seven:
"I'm making this up as I go along. . ."
Design a file of generic NPCs, locations, encounters and other events ahead of time and keep them handy. When the players suddenly venture to the unknown (and they will), you'll be glad you did the homework. Just cut 'n paste your "spare stuff" to create settings, events, and encounters on the fly.
Rule eight:
Gather intelligence -
Ask your players what they want to see in a game - if there were some master villain they wanted to square off against, or some sort of adventure they wanted to try. Don't forget to look at the character's background - there might be dangling story threads left unresolved. Communication is the key to satisfying games.
Rule nine:
Too much planning sucks -
If you take a solid week to plot and plan out every corridor on the enemy starcruiser, build the crew in detail, devise the perfect base/stronghold for these pirates to operate out of, all for the climatic battle of your game - your players, without fail, will sneak into the base, never be detected, and blow up the reactor instead - and end your game in half an hour.
Come up with an overall outline - and make it general as possible. Plot out what the bad guys are up too, and what will happen if they are left to their own devices without PC interference. Keep your notes open ended, with a couple of key maps if so inclined, so that when the players come up with an unexpected back door, you can be flexible.
Rule ten:
The Twist -
Halfway through the story, when the players think they're just about to complete the mission, throw in a big twist. Just when they rescue the princess from the moon (whoops, that's no moon, that's a space station!), she tells them they've got to take a droid to the rebel headquarters because he's their only way to destroy the biggest threat the galaxy has ever known.
The twist should change the goal of the characters and lead the story down a different path. Maybe they've found that somebody is a traitor. Maybe they just learned they're in an ambush. Whatever it is, it breaks the storyline away from what it was and takes the characters down a whole new path.
Rule eleven:
It's the player's game too -
Do your players devour mystery novels by the dozen? Spend all their free time watching westerns? Then make the adventure a mystery story. Put in a few gunslingers and calvalry officers. Did they love that horror adventure you played, but fell asleep playing the spy mission? Don't do any more spy missions, or if you do bring some fear into them. Some people like the pure hack 'n slash adventure, while others might want to avoid combat altogether in favour of mystery and intrigue. Go with what they like, if they enjoy the adventure you will too.