Written by MSG Commander
Back when you met Josh in the Fortune-teller's house, you learned from Paola that the Fortune-teller is actually a witch like herself.
What's more, witches in Laft and Illumica sometimes get requests from the townspeople, and since you're friends with Paola, you can also take on those requests for them (and get some pretty good rewards).
A lot of the requests are simple - for example, collect 10 pieces of Iron Ore and turn it in for 1 piece of Iron.
But the cool thing about these requests is that, once you complete it, the Material you were sent to collect becomes available for purchase in the Supplies Shop! (So, throughout the course of the game, a lot of Materials will become available this way.)
There are other requests to kill a certain number of monsters - these requests don't give much in the way of a reward; however, you can usually complete these requests while you're collecting Materials for the other requests, killing two birds with one stone.
The hardest requests are the "Boss" requests - requests to kill a single, boss-type monster in a specific dungeon. A lot of these requests offer really good rewards, plus the bosses often drop useful items or accessories.
The Witch's Request Boss Guide gives more details on when and how to defeat these monsters.
Before you go to Elyups Cave, you should do as many of the witch's requests from Ensen Hamlet as possible. You don't have to do them all, but the more you do now, the easier Elyups Cave will be.
You can easily complete all the requests except for the Savage Dragonute in the Mine (save that until you're at least Level 25).
If you complete these requests, and then talk to the witch again, it will unlock an additional set of requests. You can do these requests now as well - just save the "Boss" requests until after Fred is back in your party.