A few thoughts...
For characters, a good idea is to try and develop each one to the point that they come across as their own person. To do this, you'd need to make decisions about how they speak, what they like or dislike, etc. Doing this will define the heroes and villains, and make them more individually identifiable. I'm not talking about writing a twenty page dissertation on each one, but making sure they have their own quirks and traits that come through in their dialogue or actions is a good thing. It would also be good to have reason's for why they talk or act as they do.
For the text itself, allow players to set a "speak speed" (how fast the text comes up). If you want a prime example of how not to do cinema text, play Valis: The Phantasm Solider on the Genesis.
Keep your character roster diverse, but trimmed. It's cool to give players the sense of a world filled with individuals, but you'll create a better world by having a well developed set of fewer characters. It's hard to grow closer or more attached to eighty different characters. Instead, focus on a core group that are important to the story (on both the good and bad sides), and let the players see the world through those characters' eyes.
Don't make the players go all the way back through caves and dungeons they've already had to go through earlier. It's tedious, it's dull, and it's a trait that needs to die off. Fresh new territory is much more enticing than having to walk through Demon Cave a second or third time because some dipshit ran off to hide in there.
MAKE AN ENDING THAT'S WORTH THE TIME OF THE PLAYER! I can't being to describe how utterly maddening it is to play through a game for 40+ hours, only to have the ending done and over with three minutes later (this includes credits rolling). Phantasy Star IV has a great ending for an RPG... Sword of Vermillion doesn't.
Try to let more of the story play out through events in the game, rather than through pages of dialogue and narrative. Sure, some dialogue and narration can be used very effectively, but when you wrap the player up in the events that would have otherwise just been a page's worth of text, it draws them in more.
Don't be afraid of using graphics in needed narration points. A few images that detail key aspects in the narration are more interesting than just big blocks of text. This works great for things like characters talking about some key event that happened to them in the past, or when a character is talking about a legend they remember... you know, stuff along those lines.
If you have a main villain, try to make their evil deeds stem from something other than "HAR HAR! I'M AN EVIL PRICK!". Give them a real reason as to why they're doing what they're doing... something that the player can evaluate for themselves. The more tangible the reason, the better.
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Okay, I guess that was more than a few. Sorry.