Recently got a copy of Civilization for the amiga, along with the manual and a very cool looong strategy guide. So I've been playing it a lot again.
Some random thoughts that spring to mind:
A lot of little tricks to earn money that I never thought about before
(Sell barracks before they are outdated by conscription and later combustion, f.x.)
I can't believe this one never occured to me. Late game, it takes a big city 3 turns or so to build a courthouse. Under democracy, you have no corruption making the courthouse useless. But.. you can build it, sell it for 80 gold and built it again. Voila.. tons of money to incite revolts.
Don't want the senate to force a peace treaty with your enemies? Refuse all attempts at negotiations.
Never underestimate the defense of riflemen or the AI's willingness to build 5 of them in every damn city.
2000 gold to incite a revolt may be small change compared to the piles of bodies required to take it.
Some wonders are absolutely essential (Hoover dam, womens suffrage spring to mind) others are fairly modest improvements that can be built or ignored (capture later to earn points)
Finally understanding how pollution and corruption is actually calculated (I knew the basics but its nice to have the formula)
There's a certain simple charm to the original Civ. Each game has thrown more and more factors into the mix and given more stuff to keep track of. Im not opposed to complex games (I like Steel Panthers and Hearts of Iron f.x.) but for Civ, I like it a bit simpler.
The original combat is also by far the best. The various hit point schemes caused all sorts of trouble of their own.