I think that you're better off - at least to start with - ignoring the Bulletin Board missions that require *you* to actually source the goods first (double arrows) and concentrate on the ones that supply you with the goods in the first place (single arrow for courier missions, single arrow with a cargo canister for delivery missions).
https://www.reddit.com/r/EliteOne/co...on_typesicons/
Doing the missions where you have to find the goods first, or doing standard trading, means looking into the imports/exports and economy types for different systems... There are lots of online tools for this, but they're not that great at the moment as we're not yet in the same galaxy as PC/Mac players so aren't sharing the trade data.
Try from here for some tips and links for rare goods trading and other stuff:
http://www3.britxbox.co.uk/forums/vi...rt=90#p1564869