"Slacking" is probably the biggest reason for not going up a level. I remember I used to automate workers... I had trouble with the whip. I didn't want to micro my cities (still don't, so don't do that enough). And so on. Now I'm at Monarch, and I'm quite certain if I went to the trouble of microing everything I would be at Emperor. But I rather slack and stay at Monarch
most to the point advice.
Jake, I don't know where your play is lacking but I suggest sticking at noble and trying variants.
I'd even suggest variants + reloading to try out different approaches when you feel you slip down.
My suggested progression is :
1) - go for domination on a pangea-like map. I put this in first place, because this is the most straightforward victory condition, where you need to go to war and to build up your empire.
How ? I found the best way to do so is to find a game here on the forum with enough details to "copycat" what was done. I was stuck at noble for a while, couldn't beat prince until I tried to redo what Hendrickszoon did for GotM 2. He had written a really good spoiler, not detailed enough for me to get the exact same score (his was over 200k

), but detailed enough to have an idea of what he was doing and what for. Try to find a game somewhere, meeting your level and version, and try to cope and copy it.
This should lead you to a shameless copy and a confident victory. I promise you after that, you won't see the game with the same eyes.
2) - go for cultural, on a continent map. I put this in second place, because it will help you understand a few tricks in the diplomacy department (staying away from unwanted wars, tech trading with a plan, spreading a religion for world peace) without too much concern about who's leading the race. This is mostly a "solitary" victory condition, where you learn the price and value of peace.
How? There are some articles about cultural victories. I suggest going into cottage spam mode, this will allow you to understand the value of workers, growth and commerce. If you do it right for the cultural game, you will never again be trailing in the tech race

.
This should lead you to an almost failsafe way tovictory . Once you master this way of winning, you know you can win most games regardless of your neighbours and map. Confidence should be high now. And your toolbox should be a bit stuffed in those areas :
- expansion
- commerce through cottages
- religion spreading
- basic diplomacy
- culture mechanics
3) Conquest on a small pangea-like map. This is the easiest (almost cheesy) victory. This will help you understand the power of military.
How ?
Build a few (2+capital is plenty, 1+capital is just right) high production cities, tech to archery and horseback riding while building barracks, build HAs non stop. Raze everything on your way.
There are numerous games each month in the GotM spoiler threads you could try to redo.
After this, you won't see a small tech disadvantage as a lost game anymore. The AIs suck at warmongering, and you can always take some advantage here.
4) Space race on a continent map. If you're a chicken, you can choose your neighbours

. This is not my favourite way to win a game, but it's the one which forces you through the techtree.
How? there are articles about the space race, and mostly there are loads of SGs, GotMs showing how to get it done.
It's not very difficult once you understood (see 1) how to expand into a dominating position.
After those 4 games (try to restart the same game until you get through for each "lesson"), you'll be laughing at those noble AIs

.