Death, slow down. Remember, creating is like training for a marathon - not a sprint. Take one "mile" at a time and expound from that point. I'm not sure where you are at with characters, plot and storyline but try this...take one thing that a major character did or said and depict how it effects another major or minor character. Remember the "ripple" effect and that every action has a reaction. Every good creator will give a major character an antagonist or someone that will take them to task every step of the way...kind of like my wife-Ha! Don't try to "save" your entire project by doing a quick and careless "blanket" fix. Take one character, situation, relationship and page at a time and you will see how it will stir more ideas and sub plots. Quality over quantity. There's no shame in tearing a page out of that notebook and tossing it away for a rewrite. Any new characters must be introduced gradually and sparcely - too many too soon is creative suicide. Make your audience fall in love or grow to hate your new characters. Nothing is worse than having an audience not care for your characters, they will be turned off immediately and grow apathetic towards storylines. This is just my two cents - good luck and recharge your creative batteries and remember to stop for water on your way to the "marathon" finish line!