Few players do it. I don't bother with anything more than a couple of fields and some towers. Maybe a Temple and a Fortress if it's a forward CC. You can remind yourself by watching a couple of Rise of Nations gameplay videos on Youtube.

Carthaginians bring wealth and prosperity to Kush. Played against a Hard Petra on Marmara map.   Cart_VS_Kush_H.zip

Nice work @Alexandermb I believe that the earth is a bit too bright/saturated.

Can you remind me? This was over 20 years ago for me. I remember one would build cities, and things around them, but I don't remember why this was necessary, and not end like in 0 A.D., having almost everything you need around only one city. In any case, I wonder if something could be done to make it a bit more realistic and force expansion, for example, to have limits for each building type around each CC. Surely this was discussed at some point.

Should the construction of fields right next to the civic center be reconsidered? I know it's intended to utilize the civic center as storage, but it looks rather unsightly. Also, what if the storage actually contains resources - the amount workers collect and load into it—and it could be looted?