Of course, I and much more interested in characterization, and I let my characters -- sometimes -- write themselves, so I'd be more concerned with how to develop interesting characters (the rest pretty much flow on their own). Inter-character conflicts, sub-plots -- all of these add to the complexity of the general story arc.
And, naturally, I don't have a guide for the really
hard one yet <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
I'll try my best on the fly, though <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />Interesting Characters
Basically have clear motivations/goals and are unique in at least one respect, be it in personality, skill set, or anything else. If a reader sees a character who is clearly heading somewhere, they will want to go along just to see what happens. A drifter character with no basic goals and no idea of where they are headed will only sustain short term interest as the story will ramble pointlessly - all stories being a reflection of the character(s) they revolve around.
Interesting characters can also be created by taking a stereotype from one genre and throwing it into another where it is forced to adapt to a situation it would not normally encounter, though this works better for secondary (Supporting cast) characters than for primary ones.
As an example of the latter, I once put the stock 'Love Interest' character for a swashbuckler into a story with my favourite Sorceress. As a result, the poor girl turned into rather an interesting foil for my lead, though she hated both the situation and the 'Evil Witch' <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
(That story is here
if anyone is interested.)Inter-Character Conflicts
Conflict must arise naturally from who the characters are, and preferably from either ideological or goal-related differences of opinion. People do not 'just' dislike each other - there is always a reason, and most of the time it begins with a deep difference in perspective.
For example, a character who believes in the sanctity of life would obviously dislike anyone who thinks nothing of casually killing a foe, yet the two characters may be forced to work together by an over-riding necessity. Neither one of them is going to like it though.
At other times, characters will dislike each other because they see qualities in others that they dislike in themselves, or that run counter to their definition of 'correct' behaviour. A fastidious Elf may deeply object to a Barbarian on grounds of his personal hygiene, table manners, or habit of groping waitresses in the taverns they visit.
Note that such dislikes are not always a two-way street. Assuming our Elf is female, our Barbarian may admire her immensely and try to win her heart, seeing her as a kind of goddess. He may love the way she always smells of wild flowers, admire her grace and beauty, and not really understand why she doesn't like him. After all, according to HIS culture, he is doing nothing wrong...Sub-Plots
A good sub-plot involves one or more characters pursuing a goal that is significant only to them, and not to the rest of the cast. The warrior seeking his father's sword; the mage seeking news of her missing fiance; the arch-villain seeking to find his missing (And well loved) brother.
Whereas a good main plot arises out of current motivation, a good (Non-romantic - different rules there!) sub-plot usually arises out of a character's past. So I guess the rule here is simple - work out something of the past of each character, and see what it might offer in terms of sub-plots.
Romance is a whole other kingdom, and really needs a guide unto itself, so I won't touch on that here <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> Suffice to say the difference between a contrived relationship and a realistic one is very great indeed...