Good to see you're pleased with your progress - hope you're enjoying the game!
1. I'm frequently corrected by much better players but I can't see any amazing city spots. That said there's plenty of room for some OK cities. Where would you like to put your next city and why? If you put in some screenshots with your reply it'll probably generate more responses.
2. As per AcaMetis. So in the case of your current save, you're losing 3 gold per turn at 100% research and iron working is going to take 12 turns so you need 3x12=36 gold in the bank to research this if you plan to keep research at 100% as advised. This becomes more relevant when you start to trade for techs.
3. I would ignore the F9 screen altogether - there are some really clever things you can work out from here but I don't use it much and haven't found that stops me doing well on immortal level. I would definitely not worry about comparing your power to the AI as you can generally win militarily even if their power score is much better than yours by better tactics and managing the diplomatic situation
4. Chops are really important - they are really valuable boosts to building things in addition to AcaMetis' comment about saving them for later. You must be aware that the hammers from chopping are put into the city which owns that tile at the point the chop finishes, not necessarily the end of the turn - it can be a disaster when two cities overlap and you chop into the wrong one adding 20 hammers to a useless warrior when you meant to put it into the final chop of The Pyramids! It's worth getting into the habbit of being very sure you want to chop that forest into that city on that turn.
5. Honest answer is I don't know on this difficulty - on deity I start to worry around mid-30s but think it will be significantly later on this difficulty. The thing is you're about to get copper online and a couple of axes will be more than adequate to repel barbs.
6. I probably should try it but don't use BULL (which may be different) but this feature appears in BUG. In BUG it tells you about the gold but you don't actually get the gold - maybe a feature the developers were going to include and then decided against. The hammers are supposed to tell you how much overflow you will get from whipping but in this instance the value appears to be incorrect (I've tested this in your game.) The +1 unhappy face for 15 turns is because you get 10 turns of unhappiness for each time you whip and you last whipped 5 turns ago so if you do it now it will be 5+10 =15. This will actually be 2 unhappy for 5 turns, falling to 1 unhappy for the next 10 turns.
A few comments on your game:
- I would recommend not researching iron working as you will soon be able to trade techs and the AI always researches this and you have no pressing need for the ability to chop jungle or build swordsmen (axes are fine)
- Washington is unhappy partly because you whipped something there and partly because it has reached size 4 without any military unit in there (N.B. non-capital cities will get this at size 3.) Try to anticipate this and get a warrior into your city before it reaches this point. Unhappy citizens cannot work tiles. I don't want to give you a wall of text so please let me know if this isn't a clear enough explanation.
- settler as first build in Boston is really, really slow. Try and let cities grow a bit before building workers or settlers and use your established cities for this. If you look at the food bar you'll find cities cannot grow whilst building workers/settlers - growth is so important so try and avoid pausing growth unless you really have to. As with all advice there are exceptions but I think a reasonable rule of thumb when starting out is to build a warrior as first build in all your cities except the capital.
- for the same reason as the settler advice, I would whip the warrior in New York as it now has a granary and will regrow fast - have a really good look at the food bar, the production bar, and the happy/unhappy faces before and the turn after whipping
- have a look and see if you can see a better tile Boston could work that is currently wasted?
- now that you have writing, if you click on an AI you can offer a trade proposal to 'open borders' - I would do this for every AI. This enables trade routes with them eventually and starts to build positive diplomatic relations. Furthermore, your units will then be able to enter their land.
- Boston was founded several turns ago but still doesn't have an improved tile. I would have tried to get a worker to improve the cows on the same turn it was founded - excluding your capital, new cities are fairly unproductive if not working an improved tile
- other people might suggest otherwise but based on my understanding that this is one of your first games of Civ let alone Civ 4, I would be tempted to start the fun soon by planning for war. To this effect, I would aim to get the construction technology ASAP. In the meantime I would build axemen in all your cities. Once you have construction and ~10 axes and catapults I would move them to the Spanish borders and declare war (DOW) Isabella.
Please do ask if any of this is unclear or if this is too simple - you seem to be progressing fast but this game can be very daunting at the outset. Apologies if any of my advice is contradicted by superior players especially
@lymond who although he has never directly advised me is a source of inspiration for my own progress in this game