Throughout the game I never left my original continent except I circumnavigated the globe early on with a caravel/world map trading. I never set foot on another continent except for a couple explorer units. I had 6 cities for most of the early/middle game, founded a 7th city later, and absorbed an 8th city on the edge of my continent from Cyrus (he founded a crappy city on my continent earlier) towards the end. Essentially I operated on 6 cities for a long time.
I had no iron, no horses, and no aluminum. As Catherine, I never even got to use my Cossacks.
I ended up winning by SS around the 1950's.
I did it by always focusing on research early on, with lots of cottages and requisite buildings, and trying to prioritize techs that further improved research. I missed all the early wonders/religions like I said but got to education/liberalism first and my research pace took off nicely. Some of my cities sucked in production initially but that was to be expected with my approach. I tried to keep the other civs pleasant or better towards me and I was able to trade for a LOT of different resources (I didn't have a variety of resources on my continent but some of the ones I had, there were multiples of them) and a fair number of techs. Only exception was Montezuma with whom I warred 3 different times - with the 1st one happening when he sneak attacked me around the middle of the game (my riflemen/grenadiers fought him off my continent).
On the other continents, Mao was periodically warring with Cyrus (I think I bribed Mao into fighting Cyrus one of those times, don't remember) towards the west, and Gandhi/Montezuma were struggling with each other on the east continent, with Monti having the clear advantage (for most of the game). Roosevelt was cruising along nicely on his own continent, and Hatty had a couple of smaller continents to the east and was coming along as well.
Cyrus was cautious during the middle ages but I managed to keep Mao on my good side and traded lots of resources with him. I eventually got Mao to give me iron so that problem was alleviated. Eventually I got Cyrus to be pleasant towards me as well. I cultivated a good relationship with Roosevelt and he was friendly to me. Hatty was pleasant, and Gandhi, initially annoyed, got friendly to me later on due to trading and my helping him in a war with Monti in the late game.
Around the early 1800's, I was considering possible routes to victory. At that time, all civs were pleasant or friendly to me except for Cyrus who was still cautious at the time, and Monti who was furious (around this time I was warring Monti for the 2nd time, along with Mao who I bribed to also fight him). Monti was the largest civ atm and nobody really liked him. I looked at the possibility of a diplomatic victory since I had no aluminum. I built the United Nations and sure enough, Monti was the other candidate. I got voted Secretary-General unanimously

. Cyrus got pleasant to me due to the trading etc. I decided to try for a diplomatic victory:
Even though both abstaining members were pleasant to me at the time, it wasn't enough to get their votes. So I was considering I should either shuffle the population a bit or get Cyrus/Hatty further on my side which wasn't easy. I didn't really want to go to a real territory-grabbing war with anyone because that might upset the delicate diplomatic balance I had. Mao was barely able to vote for me and another -1 modifier might make him abstain.
But then something else happened. I suddenly found out Roosevelt had obtained another source of aluminum and was "friendly" enough to trade it to me. What's that, you want 3 of my resources plus 30 gpt? Sure, sounds fair to me...
I had not been letting up on research at all and was still ahead in tech so I considered shifting my gears to a SS race. I was competitive in production despite all my cottage spamming because I had built the Kremlin earlier and rush-bought all factories and built the Hoover Dam or whatever the wonder is called now. Although I only had 7 cities at that point, I preferred a SS victory if possible, so I went for it while keeping the option open for a diplomatic win.
During this time that pesky Monti warred again with Gandhi. Gandhi asked me for help. I...accepted but didn't actually lift a finger. Not a single transport of mine went over to Monti's continent, and vice versa, because in my effort to slow down Roosevelt (#1 in score at that time and rival in SS construction), I bribed him into attacking Monti.

Monti finally found himself on the losing end and began to lose some cities, and his population went down enough so that eventually Roosevelt took his place as the candidate for Secretary-General.

Once that happened, my chances of a diplomatic victory went down the tubes (although I could still get voted to SG).
Still, due to my edge in tech and the Space Elevator, I was able to complete all the parts before the AI by 1952 AD. During this time Roosevelt kept upping the price on aluminum and I paid an arm and a leg for it but was strong enough in commerce that it didn't matter. Due to my late boost in wonder grabbing, I also got a lot of late great people, so I got myself two Golden Ages (yeah, 5 great people including the late great engineer via Fusion) which really helped with SS building. I culture-absorbed Cyrus's city as my 8th and final city but it didn't contribute to SS building much.
A shot of my empire and the world 1 turn before the win:
Demographics:
#6 in land size but #1 in population
This shows I was hovering at the bottom in score till around 1200AD. then the slow, painful ascent began, finally overtaking Roosevelt in score at the very end. Cyrus lost some wars against Mao in the midgame, and you can see how Monti lost his latest war near the end.
Overall, it was a fun game. Despite the lack of resources, I survived through trading and keeping good relations, and focusing my few cities to produce commerce. I was also aided by some of the other civs slowing themselves down due to war and keeping Roosevelt friendly all the way was very conducive to the SS win. One would think he'd stop trading me Aluminum altogether at some point but he never did, just kept raising its price like 3 different times. Thanks Roosevelt, you've been a true friend
Savegame 1 turn before my win is attached if you want to take a look.
View attachment 111619
This was my first ever win at emperor. I always like to play all default settings and standard continents (at least initially) because I feel that all other kinds of wins are...non-standard

Right now I'm trying out another standard emperor game with Elizabeth, and it's a completely different game because I've got a pretty large continent with 2 competing neighbors - Napoleon and Mao.