The ONLY resource set you should be going for is the FastFood/Beer... dammit, I've written this before in private forums.
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Wheat and Fish? This is awesome. The ONLY trade set you should have is the best trade set in the game. It's known as the FastFood/Beer/Construction set, aka the 3BR (three bonus resource) set.
The eleven essential trades:
Cattle, Fish, Aluminum, Water, Marble, Spices, Pig, Iron, Lumber, Sugar and Wheat.
That leaves one optional resource for you to choose. I'd go with uranium (so that you can buy nukes later on, and get a money bonus), though coal (big land and infra bonus) and gems (pure money) are also popular.
With a Wheat/Fish combo, any trade set besides the 3BR above is a terrible waste. Give all of your partners who don't fit in with this a day or twos notice, then drop the trades and get new ones.
Try not to collect taxes until you've got your trades set up. Join a 3BR trade circle that wants Wheat/Fish. 3BR is pretty popular, you'll have little to no trouble finding one.
Also: Alliances are a great source for trade partners and advice.
Regards,
Rail.