Some of my stories are good examples of the problems you'll run into when starting out on a tale without any sort of idea about how it's going to end and introducing too many characters without purpose. Each time you introduce new characters, you complexify the plot and increase the risk for plot holes. Some of my stories are punctured beyond repair and I will probably be better off to just give up on them and take my lesson home on what not to do.
I feel it is better to keep the plot as simple as possible and it will most likely take care of itself. What fantasy exactly gets you aroused? Think about it and write it down; then (the hardest part for me) stick to it!
"Kangaroo Land or the Samboy Chips Game" is probably my biggest blunder. It starts all right with a group of preppies getting caught by an old depraved sheriff and his even creepier friends, his psycho son and then a bunch of Aboriginals. This is a great premise of rich folks from big town vs. poor countrymen getting back at them. All I had to do from there was to keep those girls stuck in the Aboriginal village and describe their suffering and debasement. Had I done that, I could have described what Elsa and Tricia get according to the kinks and depravities of Tarzan and the rest of his sordid bunch, until something saves them, or they find the adrenaline strength to escape, or they just stay there indefinitely and try to get to terms with their new life of whores for Aboriginals.
Instead of sticking to that simple plotline, I kept adding characters until the story became a convoluted mess that got increasingly hard to follow and increasingly less believable, and every time I tried to fix the thing, I came up with even more characters and more complexification, to the point where I'm now having a Royal visit from then-Queen Elizabeth in this Australian countryside... And two corpses at the police station, one of them being a dead deputy. Lol!
This being said, it's perfectly all right to make mistakes and learn from them. There were very sound ideas in that story. It's just that there was too much stuff crammed into one single tale. The female trooper getting gang-raped would have been better off in a separate story of its own. In that particular story, she was an accomplice, albeit a not-so-bright one.
Since I tend to add characters and complexify the plot unnecessarily as I go, I am a writer who will be best served by writing down a plan so I'll know where I'm headed to and can stay on course.
Simple scenarios with vivid scenes will always trump complex, hard-to-follow stories. Your readers will often identify with one character right from the start, and if you keep introducing new characters all the time, the initial characters just end up drowned in some big mish-mash. Some writers are great at improvising without falling into this, others need a plan.
Having a castle besieged, then captured with the women raped should be simple enough and should be all it takes to make a great story, especially if the writer focuses the attention on just one or two main characters.
