At the risk of sounding like a noob, what does it mean when I try to make an item and it tells me that I 'lack the expertise'?
It means that your tech aptitude in the given field is too low. When you open up the schematics screen, there'll be a number in the upper left hand corner of the "ingredient" box. That's how high your aptitude has to be in that given field (like chemistry or firearms, etc). You can use tech manuals to boost these until your aptitude is high enough. These game related questions go in the Hints and Tips forum, btw.
to check how high your apptitude in any tech is, go to the character screen, go to schematics, the blue number in the little box near the top is your apptitude...
Also, if you lack expertise in the given field and are to damn stingy to alot any CP to the field, a bookseller in Tarant has tech manuals that you can buy that increase your expertise in the given field by as much as your intelligence. Buy as many as you need and can afford. You can use this as a magically inclined character to make stuff like the pyrotechnic axe, which just requires the featherweight axe and fuel, both of which are sold at the blacksmith in Caladon.
