First Aid - there is a vendor in Stromgarde Keep in the Arathi Highlands that sells three books; one will teach you expert first aid, one teaches heavy silk bandages, and the other teaches mageweave bandages.
Cooking - there is a vendor in the Silverwing Refuge south of Astranaar in Ashenvale that sells an expert cookbook.
Fishing - there is a vendor in Booty Bay that sells a book that will teach you expert fishing.
Wild Steelbloom? The lowest level I know to find that is in the Wetlands.
(All of these answers can be found on this site - the trade skills sticky will answer the first three, and the best way to get an answer to "what is a good spot to find..." is to use the search block and look at the maps.)
I've found since this thread that you can find a lot of wild steelbloom in the barrens coming from ratchet then heading south on the east side of the barrens going toward thousand needles.