The thing with worldbuilding is that it's all too easy to fall into the old info-dumping technique. You're the Creator of your world, and of course you want to acquaint the reader with its grandeur so at the very first instance, you bombard us with several long paragraphs detailing every hill, castle, and hybrid creatures existing in your creation.
Um, not good. You'll run the risk of putting your readers in snooze town.
Or you can go the other way: You skimp on the worldbuilding descriptions to allow for a fast pace read.
Erm, not good either. If we find ourselves scratching our heads, then it means you've lost us. How the heck are we supposed to know what a kipa is, and why does your character keep saying "sika!"? (Those are actual words found in my MG Fantasy WIP. :D )
There has to be balance. The aspects of your world should be interwoven within the scenes and around your characters' actions. A sentence here or there explaining certain things will not bore your reader (as opposed to huge blocks of descriptive text).
Here's an excerpt from my MG Fantasy WIP:
Ascan opened his eyes too fast and stars blinked in and out of his periphery. Seagull wings flapped overhead in frenzied beats as a couple of fishermen hauled in their half-empty net. Men groaned even as they began to haggle for prices.
“Pan! Pan de sal!” This came from a pudgy man carrying a woven basket on his shoulder. Ascan had only been in Dagatur for a week but he’d already learned a few necessary words in the strange, lilting language of the fishing folk. Pan was bread. Not gutted fish, not slimy octopus legs, not bitter sea kelp.
Real doughy bread. Ascan’s mouth watered.
A horn tooted, signaling the arrival of another ferry boat. A boy, half Ascan’s size, scampered by him. The beggar kids who’d been busy harassing the fishermen for a centi all morning long scattered and disappeared, sweeping the docks clean of their filthy rags. Ascan squinted at the incoming boat, noting the insignia fluttering in the wind. A W encased in chains.
Ascan crept toward a group of buyers vying for a bucket of pint-sized squid. He would be safe enough in a crowd, if no one notices him. And lately, no one had noticed him—his ghostly hollow self flitting around the docks on wobbly legs. It had been three days since he last ate a stolen meal.
In Dagatur, the slave trade flourished where the fish did not. Stowaways washed over the harbor with every tide, and stowaways usually meant orphans. A long time ago, it was said that the Watchers cared for the orphans during the great War, housing them in sanctuaries, and teaching them so they could be brought up in useful trades until they come of age. But the War had long ended, and now, the only trade they were brought up for was one that involved scrubbing rich fat men’s backsides, serving them their meals, and blubbering yeses like flustered hens.