Without seeing a specific save, it's very hard to answer this first batch of questions:
I am at war.
My golden age just started as my unique unit won a battle - berserker.
Would it be wise to sign peace and produce, or should I be able to control the happiness levels even if this is an offensive war?
I am a bit short on the lux side, so that is the worry, but the golden age compensates right?
And if anyone can point me towards an article on GA, I would be grateful.
Demigod level - C3C, Archipelago map with 70% water.
Yes, the GA produces additional commerce, so that will help with happiness. Some other questions occur to me, though:
(1) Did you DOW the other civ, or vice versa?
(2) Are there luxes or resources that you can capture?
(3) How many luxes do you currently have?
(4) Do you have markets up and running?
(5) Who is your opponent?
(6) Where are you in techs and what sorts of units are you using and facing?
(7) Is there anyone else that you can drag into the war on your side?
I'm sure there are other relevant questions, but those are the ones that strike me right away.
I'll take a shot at this one, though:
Edit: oh, and one more thing; what improvements do you usually build in specialist farms? And how big do you usually let them cities grow?
1) Usually, none. Now and again, a particularly food-rich farm will get an aqueduct, but that's the exception rather than the rule.
2) As large as their food supply will allow. Building along riverbanks will let them grow past size 6 without an aque, so that's advisable if they've got enough food. Building them on hills also gets them up off of grassland and increases the available food. Same with tundra. Turns bad terrain into a 2-food tile (maybe 3 if agri).