Generic advice for now. Find one mentor, you're getting conflicting and confusing advice in this thread. Ideally someone in your world, so post your world here.
There;s nothing wrong with asking for advice in the forum, I highly recommend it, but you should try to keep it to one topic at a time. So far you've covered Happiness, GBs, Goods, getting plundered...
All things we'll be happy to help you with, but maybe stay with one at a time?
So pick one and we'll be happy to help you out.
Below is some specific advice, but as I said, find a mentor from your world and work with them.
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Don;t be afraid to experiment with your city! There is only one irrevocable mistake players make, advancing in Era too quickly. So take your time and ask and learn and PLAY!
If you're doing fine producing and trading BA Goods, then produce and trade BA Goods.
The conventional wisdom has been that you produce current Era Goods and trade down (In your case building IA Goods and trading those for BA Goods) but that may need to be revisited with the advent of GBG and the increased demand for lower Era Goods.
Don;t sweat GBs right now, they'll come to you when you need them and figure out what you want and need.
Regarding getting plundered this is what I give all Guilides:
Plundering is explicitly within the rules, is encouraged by INNO, and is a successful strategy. Don’t waste your time getting upset at being plundered. Take these steps and you will reduce your losses to a minimum. If all else fails, be patient, hopefully you’ll rotate to a nicer hood in a couple weeks. In order of effectiveness.
TAVERN BOOST CITYSHIELD. Expensive but it does the job.
PLUNDER PROOF YOUR CITY, Have no plunderable buildings.
COLLECT ON TIME. Set your production to finish at a time you know you will be on to collect. Many plunderers will stop attacking if you do not give them anything they can take.
FIND UNPLUNDERAB:E GOODS SOURCES. Babel, Lighthouse, St, Mark’s, Frauenkirche, Royal Albert produce unplunderable goods. Special Buildings, including Wishing Well, Fountain of Youth, and motivated Tribal Square can’t be plundered. Recurring Quests can provide Goods.
MANIPULATE YOUR NEIGHBOTHOOD POSITION. Players at the bottom of the hood seldom attack the top players in the hood. Slow down your Tech and Continent growth and put some time and effort into acquiring and leveling GBs. This will move you up higher in the hood.
GET YOUR BUILDINGS MOTIVATED. Switch to 24 hour production, AND reduce decorations, AND increase your friends list AND Aid everyone every day. Motivated buildings can not be plundered. By doing the four steps your houses, supply buildings, and other motivatable buildings will always be motivated. Triple bonus from this: 1) if you miss collection, no big deal, your production is safe until you can collect. 2) Your coin/supply production will go up! Motivation, besides stopping plundering, doubles production. 3) You only have to collect once a day.
PUT UP YOUR BEST DEFENCE: The more units you kill, the less often plunderers will attack you, they will target easier prey. If you are not inflicting any casualties try changing some of the units in your defense. Watchfires, Ritual Flame, some Special Event Buildings, Monastery, Deal Castle, St. Basils, Terra Cotta, and AO help with defence.
COUNTERATTACK PLUNDERERES. If you can, take back that which was yours. Even an unsuccessful attack may dissuade a casual plunderer.
TRY DIPLOMACY. Ask plunderers nicely to stop. It may work. If they want to be paid off it’s up to you, but I’m not a fan of blackmail, giving or receiving.
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Good luck!