One of the best ways to generate tension and conflict among your characters is to have them argue with each other.
I know that in movies, action seems like the safer course, but once the fighting is over, everything reaches a new status quo rather quickly. There is a victor, a vanquished, or the two sides fight each other to a stalemate...those are your basic options.
An argument, on the other hand, can reveal things about your characters that even you hadn't realized yet. For example, in the scene I have been writing for the past few days, one character (Seff) has to convince two other people (Kirth and Vestra) that he has an urgent message; their keep is about to be besieged.
That sounds important enough that Kirth and Vestra ought to believe Seff, right? Unfortunately, Seff is from a country that Kirth doesn't trust and Vestra doesn't know much about, so they are doubtful of Seff's truthfulness.
In this same argument, Kirth and Vestra need to convince Seff that there is a danger from another place...a world that none of them even knew existed until a few days earlier. Consider that this is set in the dark ages, that Seff is from an insular society, and that his country is constantly battling Kirth's--you can see why there's a significant level of disbelief going on throughout this conversation.
Another way that an argument is better than a physical fight is that it makes the characters deal with each other. Rather than simply having your characters trudge from plot point to plot point, this gives them the opportunity to discover what other people in their world care about. What angers Vestra? What would push Kirth to violence? How much does Seff really care if these two believe him? An argument has far-reaching consequences...anything from hurt feelings for the next few chapters to outright war over a misunderstanding.
A final element to consider once you have your debate points lined up, is the setting. In my example, the argument occurs in a desert, right after Seff has tried to attack Vestra. (Kirth intervened, saving her, but now Seff needs to explain himself. It's a long story, so I'll let you know when the book is finished.)
This argument would not have had the same effect if it had occured in the garden of a castle, or in Seff's homeland (or in Kirth's country, for that matter). The austere, harsh setting of the desert magnifies their argument, because the longer they stop to argue, the worse their situation will become. After the brief fight and protracted debate, will there be enough water for all three of them to reach an oasis? Is this an argument that can be settled quickly, or are they better off to table the discussion until they arrive at Kirth and Vestra's keep?
When writing up your arguments, consider these 3 things:
1. Which characters are involved?
2. What are the rules about arguing? (Are there traditions that need to be observed, or does the person with the loudest voice win?)
3. Where is the argument happening, and how does that affect the argument? (For example, the same argument would happen in whispers if it occured in a library. On a soccer field, shouts would be more acceptable.)
Have fun writing, and let me know if this was helpful to you. Thanks!