Advantage Ball: Carefully minded throughout. At the beginning, Adhemar has the advantage by virtue of his greater experience, but once William finds his feet and begins to feel more confident, he begins to win easily. At the end, Chaucer's Rousing Speech gives him the edge he needs.
The real Ulrich Von Lichtenstein — yes there was a real one! — was a 13th c. knight who, on one occassion in his career of errantry, rode the tournament circuit in the guise of 'Queen Venus' complete with silk gown over his armor and long braids of false hair dangled beneath his helmet. He was a huge hit and the tour a massive success with a final score of three hundred broken lances without a single fall. Somebody really did their research to unearth Ulrich. That or they read the Horrible Histories book on knights.
During the middle ages, blacksmiths paid their taxes to the local feudal lord in arrowheads instead of gold, so nearly all blacksmiths' wives were trained in basic smithing in order to make arrowheads and free up their husband to do the earning jobs.
Word Of God states that the musical anachronism (as well as some of the dialogue "It's called a 'lance', hellooo.") was done intentionally to illustrate that people of the era thought of their music pretty much the same as modern people do of current music. No such excuse for the clothes, though; the costume designer simply though they looked neat.
Aristocrats Are Evil: Adhemar, the evil rival, is Count of Anjou. On the other hand, the prince is a good guy, and the hero's friends are seen making up stories about how evil his aristocratic opponents are in order to encourage him to beat them. It works a little too well.
Berserk Button: Roland is initially unwilling to gamble all of their money on the Paris tournament, ignoring the taunts of the Frenchmen, until they go to far:
Frenchman: And most importantly, because the Pope himself is French.
Roland: ... Well the Pope may be French, but Jesus is English. You're on!
Big Game: The world championships. At which William and Adhemar are finally to meet.
The Blacksmith: A female one, no less, acting as a farrier and armoursmith.
Blatant Lies: Prince Edward justifies knighting William by announcing that he's discovered Will is descended from nobility, then basically dares anyone to call him on it: "This is my word, and as such is beyond contestation."
Cerebus Callback: In the scene where William first arrives in London, he imagines that a young boy cheering him on is himself as a child. Later on as he sits in the stocks the same boy runs up to him and slaps him in the face.
The Champion: Despite being motivated to joust for a variety of personal reasons, partway through the movie Will is ready to lose every single match he competes to prove to Jocelyn he is her true champion, putting at risk all these other goals.
Curtain Clothing: "Eh...green. Um...trimmed in a kind of...pale...green...uh, wi-with, uh...wooden toggles."
David Versus Goliath: A plucky peasant with an antique suit of armour versus the combined nobility of Europe and, more specifically, the undefeated champion of Europe.
Dance Sensation: Both in the opening song and the ballroom scene.
Deliberate Values Dissonance: Played straight, then subverted. William is stripped of everything, put into the pillory, and humiliated for daring to rise above being a peasant squire. Then the Prince knights him anyway.
Dirt Forcefield: Mostly averted, as characters appear just as dusty and dirty as they ought (and the Black Prince has a bad case of Helmet Hair when William reveals him), most of the time. Played straight, though, when Kate is shown working on the below mentioned Nike armor; a blacksmith working in her forge ought to be covered in soot, while she's just got a little bit of dust on her forehead.
Fake Brit: Australian Heath Ledger and American Alan Tudyk both put in pretty convincing performances.
So convincing is Tudyk that he's often mistaken for being Fake American; he's from Texas!
Forging Scene: William gets new, light-weight armour after his new friend the female blacksmith undertakes one of these.
Grand Romantic Gesture: Will purposefully loses a jousting match to prove his love (getting beat up in the process); to paraphrase Jocelyn, when Will tells her he'll win the tournament for her, "You would win the tournament anyway; if you want to prove your love, you will lose." Then, once he's taken his lumps, she sends her handmaiden to tell him if he loves her, he'll win the tournament. This does not go over well with William, or his friends.
Chaucer: There she is, William. The embodiment of love. Your Venus.
Heroes Prefer Swords: Before he gets the hang of jousting, swordplay is easily William's best skill.
Hollywood Healing: As soon as William wins the championship, he can move his arm without difficulty. And there's no mention of removing the piece of lance stuck in his shoulder, which would be very risky surgery in that age.
His arm was never the problem, he had no trouble aiming the lance, he just couldn't grip it.
Hot Blooded: Looking at him, you wouldn't think William the type. But when he finds out that his current opponent, the man his rival Adhemar withdrew from rather than face, is Prince Edward the Black? His first response is to charge the man head-on.
Informed Attractiveness: A great deal of fuss is made of Jocelyn's beauty, when the other female cast members are just as, if not more, attractive. It probably doesn't help that Jocelyn was stuck in rather unfortunate outfits and hairstyles for most of the movie.
Ironic Echo: "You have been weighed, you have been measured, and you have been found wanting."
Kate invents the Bessemer Process for heating steel 400-500 years before it happened. William is initially ridiculed for wearing thin, light armor. At least until he nimbly leaps onto his horse.
Her etching "the mark of [her] trade" (the Nike logo) into her armour, which is also received with ridicule.
Jerkass: Adhemar, upon first meeting William, immediately insults him several times and he just gets worse from there. They seem to have even gone out of their way to make him completely utterly dislikeable.
King Incognito: The Black Prince. Twice, if you count the crowd scene.
Chaucer: SIR ULLLLLLLLLLLLLRIIIIIIIIIIIIIIIICH VON LICHENSTEIN!
The Lost Lenore: A rare male example of this trope being blacksmith Kate's dead husband.
Love Makes You Dumb: William fully understands this trope, as after making a faux pas to Jocelyn, she tells him that if he loves her, he'll lose. And so, at the beginning of the next tournament, after the flag for William's first joust is dropped, and his opponent spurs on, the four members of the Five-Man Band cheering William on...
Roland: "What are you doing?"
William: (sitting on his horse, going nowhere) "...Losing."
Wat: "I don't understand."
William: "...Neither do I." CRASH!
Motivational Lie: At one tournament, Roland tells William that his opponent is cruel to his peasants. After an irate Will has charged off to thrash the opponent, Roland remarks that it's probably true.
Nom de Guerre: Two of them, both due to the men in question trying to hide their identities for various reasons:
William Thatcher styles himself as Sir Ulrich von Liechtenstein, to hide the fact that he is a peasant.
Edward, the Black Prince, goes as Sir Thomas Colville, as nobody would dare joust with him if they knew who he really was. Notably, Edward is entirely unsuccessful in hiding his identity as word gets around quick who he is.
Not Even Bothering with the Accent: Done deliberately — Laura Fraser was apparently expecting to be asked to put on a generic English accent, as usual, and was delighted to be allowed to use her natural (sexy) Scots accent.
Not so Different: A rare complimentary fashion, Edward laments how alike he and William are.
Edward: What a pair we make, huh? Both trying to hide who we are, both unable to do so.
The Oner: William and Jocelyn's long walk-and-talk scene in the cathedral.
Pair the Spares: Roland often becomes a Beta Couple with Jocelyn's handmaiden Christiana in fan fics. There are several scenes in the movie in which one can see Roland and Christiana chatting happily in the background. Made explicit in a deleted scene where Chaucer's wife visits the tournament. Jocelyn and William go off together, Roland and Christiana go off together, and Wat attempts to go off with Kate but she just gives him a cookie and walks in the opposite direction.
Product Placement: Not that the movie got any money for it, but that trademark that Kate etches into her armor? A pair of upside down Nike swooshes.
Self Proclaimed Knight: There are two. One is the classic struggling underdog, William Thatcher, the peasant who's masquerading as the knight Ulrich Von Lichtenstein, and the other is the royal in disguise, Sir Thomas Colville or Edward, the Black Prince.
Shaming The Mob: Subverted in the theatrical cut; Chaucer, having previously demonstrated his ability to work a crowd, tries to shame the mob that gathers around William when he's in the stocks. He gets as far as three words in before the mob silences him with a volley of rotten vegetables. However, in the extended cut of the film, Chaucer succeeds in Shaming The Mob into chastened silence before Prince Edward steps in. This scene was cut to beef up Prince Edward's role.
She offers to live in a shack with pigs if that's what it takes to keep William un-arrested and brings his blind father to the last tournament. Seems to fit pretty well.
Throw It In: Besides the aforementioned "We Will Rock You" opening, when Will wins his first sword match, the crowd is silent until Roland spurs them on to cheer. As it happens, the extras who composed he audience were Czech and didn't realize they were supposed to cheer when Chaucer finished his speech.
According to DVD commentary: Jocelyn's "Oh that is lovely!" in response to a priest's gesture prompting her to kiss his ring was an adlib. "Your entrails will become your extrails" was an audition adlib that helped Alan Tudyk get the part and made it into the film.
Will and his friends, who all stick together to the bitter end.
As noted earlier, this is a factor in Prince Edward's decision to rescue him. "Your men love you. If I knew nothing else about you, that would be enough."