So I did Jeff's "twenty questions" thing from some years ago for my brand new 5th edition campaign. The post is kind of long and is mainly intended for my players, but feel free to give it a gander if you wish. I stole liberally from Al-Qadim, but my setting isn't Al-Qadim.
1. What is the deal with my cleric's religion?
Depends on the religion:
*If you adhere to Samadala, your character is a monotheist who enjoys the backing of the Albadian government. Clerics of the god Samad are very similar to "standard" D&D clerics. Expect daily prayer, celibacy, and not eating certain meats. You are also expected to help the helpless, right wrongs, and kill monsters. Note that the latter duties apply to clerics; ordinary priests are not expected to fight.
*If you adhere to Ormasdism, you're kind of the same, but you're allowed to have a family and you're more prone to the wandering Don Quixote thing because your religion says that Ormasd and Ahriman are equally powerful.
*If you adhere to the Temple of Ten Thousand Gods, you're a bit more mystical and less martial. This religion is very populist and looks after the common folk.
*If you are a Sihilist, you're probably a monk, not a cleric. Expect lots of meditation, stretching, and montages where you punch rocks/trees and pray facing the sunrise.
*If you follow the Old Ways, you're a druid who pays homage to the Lords of Flame, Sea, Sand, and Wind... or possibly just one of them. Expect vague visions about things you need to do and seeing omens in nature. Also expect to protect the natural world from that which is unnatural.
2. Where can we go to buy standard equipment?
Cities all have marketplaces and bazaars where you can procure just about anything. Smaller towns and villages tend not to carry much gear of interest to adventurers unless they are on or near a hostile frontier. Merchant caravans can be found on the roads crisscrossing the desert and will often overcharge, since where else are you going to get a lantern in the middle of the sand dunes?
3. Where can we go to get plate mail custom fitted for this monster I just befriended?
Most large cities have artisan armorers. Spoiler warning: it's going to be expensive. The capital city of Maruk is host to the greatest craftsmen in the land.
4. Who is the mightiest wizard in the land?
Bakar al-Ramad, master of the Great Academy in Qalam.
5. Who is the mightiest warrior in the land?
In public, you'd probably better say the Caliph, Suliman the Righteous. When not in public, you can probably say Ramalaan Mansoor, a wandering monster slayer believed to have slain a blue dragon in single combat.
6. Who is the richest person in the land?
Fahd Othman, an ambitious merchant prince who dominates sea trade. Rumor has it that he's a legitimate business man and a devout Samadalan.
7. Where can we go to get some magical healing?
Holy men and wise women. You can find the former in most large temples and the latter in some out of the way places.
8. Where can we get cures for the following conditions: poison, disease, curse, level drain, lycanthropy, polymorph, alignment change, death, undeath?
Poison and disease can be treated by mundane physicians and village healers, although magical healing is available from temples, hakima (wise women) and the odd shrine priest. Curses, level drain, lycanthropy, and alignment change are cured by clerical magic. The best sources for that are temples in medium or large population centers, or being able to find a hakima on the outskirts of civilization. Death is never cured. Undeath is cured by destroying the undead.
9. Is there a magic guild my MU belongs to or an order I can join to get more spells?
Wizards are typically trained by a magical academy. There are two in Albadia: One in Qalam, the City of Scholars, and one in the royal capital of Maruk. Even after graduating, former students are welcome to visit their academy to exchange magical knowledge. Sorcerers and warlocks, for obvious reasons, are not part of these academies.
10. Where can I find an alchemist, sage, or other expert NPC?
Alchemists can be found in medium or large population centers, especially those that contain scholarly institutions. Sages can be found in cities, though there are some who live in remote wilderness places. Experts are usually found in the large cities.
11. Where can I hire mercenaries?
Unlike many of the other specialists, mercenaries are best hired away from the centers of civilization. Outland tribes, seafaring corsairs, or troops of professional mercenaries.
12. Is there any place on the map where swords are illegal, magic is outlawed or any other hassle from Johnny Law?
Weapons and magic are forbidden to all but the Caliph's house staff in his palace. Outside of that, possessing a weapon and using magic in themselves are not considered crimes, but actions that damage or assault others are still crimes. Usurping the will of another is considered a form of assault.
13. Which way to the nearest tavern?
Very nearly every settlement has a tavern and also a coffee house. The town of Agrama, where we've started our campaign, has one inn/tavern/trading post/coffee house, The Mighty Tiger. One of the PCs is temporarily living there. The proprietors are Ghusun, an ogre woman, and an elderly halfling man named Fatin.
14. What monsters are terrorizing the countryside sufficiently that if I kill them I will become famous?
Here in the northern part of Albadia, the hobogoblins and gnolls are feared for their attacks on border towns. Barbarian tribes from the northern mountains used to be a problem, but they were driven back after a series of border forts were constructed.
15. Are there any wars brewing that I could go fight?
Conflict between outland tribes is ongoing, as is the threat of mountain barbarians.
16. How about gladiatorial arenas complete with hard-won glory and fabulous cash prizes?
Not legal ones, no. Gladiatorial combat is considered barbaric. That doesn't mean there aren't tons of underground ones, though.
17. Are there any secret societies with sinister agendas that I could join and/or fight?
Well, if you already knew about them, they wouldn't be very secret, would they? The PCs have heard rumors about a poisoner's guild that used to have a hideout north of town. (The PCs are currently exploring said hideout) The stories say the townsfolk ran the poisoners out and destroyed them. No way any of them survived, right?
18. What is there to eat around here?
Bread, meat, and rice, with the wealthier having more meat and the poorer having more rice. Onions, figs, dates, lots of soups and stews. Oh, and don't forget the coffee. Albadians love coffee.
19. Any legendary lost treasures I could be looking for?
The Pirate King, Hizir Hyred, is said to have hidden a fabulous treasure "far from the seas." Scholars place that treasure somewhere near Albadia.
The Noor Empire that once ruled this part of the world collapsed suddenly and totally. Noorish treasures hidden away by warlords, decadent nobles, and corrupt priests can be found in all sorts of out of the way places.
20. Where is the nearest dragon or other monster with Type H treasure?
The deserts near Agrama are said to be home to a young blue dragon. I'm not quite sure how to translate treasure types into 5e, but it likely possesses the most treasure. A runner up would be the cyclops that is rumored to live in a nearby region.