There is no definitive answer for this type of question, but as a general guideline, this is how I go about creating a game world:
You should consult with your players as to what sort of world they are interested in playing in. Check out The Same Page Tool; it has been mentioned here before, and will be again.
Once you know what sort of world you want, you should probably map out at least roughly any area that may possibly influence your players, including those places over there that people talk about, but don't really know about. Make sure as best as you can that the shape of the world fits your ideas and the environment you want your players to experience.
Once you have your world map—even if it is just in your head—populate it with those things that affect daily life for everyday NPCs. Where they are the same as Earth—even historically—you needn't say too much about it (e.g., "As Earth C1500AD, except..."), but you need to detail those things that are different. You may choose to alter things to suit your concept rather than just the opposite way around, e.g. in the science-fantasy campaign I am currently running, I wanted a world with magic (with well-defined rules) but also somewhat realistic atomic-powered mecha, so I changed chemistry from Earth default so that non-gaseous oxidisers react only very slowly (making black-powder firearms impractical, thus inhibiting their development), some special unstable elements exist that can be used to power the mechs without thermal fission reactors (the element directly drives flywheels), and in the history I created, horses and related species became extinct when they were exterminated due to a magical plague that turned them into ravening carnivorous monsters, as well as magic once being more powerful than it is now. All of this meant that with knights relegated to walking and not having to fear guns, armor became powered, first by magic, then later by atomic power as magic dwindled...
As for specifics, like music, come up with as little or as much detail as you like and your players are interested in. For example, in my current campaign, one of my players didn't want to know much about music or ballet (other than that they exist), as he decided that his character detested them, but wanted to know about paintings as he decided that his character was a connoisseur of landscapes. Thus, there was no need to come up with a list of who wrote which symphony or ballet, but I needed a list of landscape artists and their relative skill, prestige and values...
Once you have the world and the societies that you need, give them some back-story by creating some history. It needn't be too detailed, just including those things that made your societies the way they are. There are some automated history generators, but IMO those I have seen seem a bit neutral, unspecific and/or tied up in trivialities. Events like "Year [nnn]: Worshippers of [deity X] from [country A] burn down temples of [deity Y] in [country B] because of [Z]", followed by "Year [nnn+1]: Authorities in [country B] persecute nationals of [country A] in retaliation for the atrocities of Year [nnn]" are a bit more relevant, as they can affect many things, e.g. NPC to PC: "You're from [country A], we don't trust your sort here..." if the historical events were relatively recent.
Once you know where your PCs will be adventuring, you may want to create some more detailed maps and some of the people they will interact with regularly.
The game system you choose may well come with its own list of fauna, flora, technology and magic, or you may need to create your own.
All this will give you the ability to create the flavor of the world for your players. Your map and the PCs travels will dictate the terrain they encounter. Other puzzles can be dropped in where appropriate—unless they commonly affect to the lives of NPCs, they needn't be pre-created at the start. Indeed, there isn't often a need to pre-create all that much other than the things that make the world the way it is and the things that everyone knows.
Since you have specified the Pathfinder system, that system (like most others) comes with its own catalogue of technologies, spells, flora, fauna, cosmology and implied societal constraints. It is up to you to decide if you want to include that catalogue in its entirety, or if you want to restrict that catalogue to those entries that match your setting, and/or expand on it with your own material. If this is your first campaign with Pathfinder (as either GM or player), I'd recommend that you make minimal changes until you have a better idea of how everything interacts and the consequences of addition or subtraction.