All of the above being said, put yourself in the moment of launch, among the masses who have not pledged and don't enter the game with the perks so many of us early adopters will take for granted. What will they want?
The top two considerations will be food and outfitting. Everyone will begin with some sort of shelter so even though that is a need, it won't be as vital at 15 (the starting age for many) as it will be a bit later. But they will need food to survive and they will be looking to outfit themselves. I say "outfit" rather than "clothe" because no one will run around naked out of necessity, at least at first. But depending on your chosen skills/crafts, you will need special equipment and tools, unless you apprentice yourself out.
Consider also that the time of the Exposition will be one of building and preparing for the invading masses. The nobility will be wanting to build up their troops. A monarch or noble who cannot protect his domain just invites casus belli to be overthrown. At the very least, you have to show those jaded masses, most of whom will be completely unfamiliar with following the dictates of other players in games, that you mean business and can protect their interests in exchange for their deference. But at the end of the day that deference you must have and that will require troops. Supplying those troops will be a lucrative business. Think armor and weapon smithing, food, gear, even healing services!
Inns and taverns will soon after take on a great importance as players set out to expand into villages, towns and cities. I expect a boom in demand for architects, masons, carpenters, cooks, and auxiliary workers. And naturally both inns and taverns will need a constant supply of food and drink. Farming will be a guaranteed income source if you go into it with eyes open and make arrangements for the security of your farm! Any local baron or baronness worth his or her name will plan on regular patrols to protect the providers of the foods necessary for the health and happiness of his or her troops and citizens.
If the players are comfortable that their needs are being met, then intermediate needs will come to the fore. Expect a demand for those skills affecting appearance and adventure. Tailors, herbalists, cartographers, investigators, animal tamers/breeders, etc. You name it, and at some point there will likely be a demand for it.
I've just scratched the surface here, of course. But the smart players will apprentice themselves out early, earning skill increases, equipment, seed money, and reputation. Consider those early months a training time for meeting the demands to come and you should prosper.
J