A quick tip for new players who want to focus on an economy-based build at first.
After 7 weeks of playing, I’ve reached level 22, built my 12th and final factory and hit 12k in wealth, mostly thanks to my companies, which provide me with a substantial daily income moving forward. I feel I’ve generally optimized my resources, despite a few strategic mistakes that I’ll try to share so you can avoid these pitfalls!

When you first started, you were probably directed to the following illustrated guide:

However, I have a few small changes to suggest in order to continue with a full economic build!

Level 23 – 12 companies
Edit: 70 energy and 31 production to achieve better optimization, even though the gain is minimal given the variation in production during operations.
I suggest you level up your skills following the guide until you reach 8 companies before respecializing as described above, in order to maximize your income early on through work and later through your businesses.
Respecialization may seem expensive, but you’re given 2 free respecializations upon arrival, and a level 5 AE produces about 15 units per day, so it pays for itself quickly.
It is recommended that you create your first four companies in limestone, concrete, iron, and steel.
This is a good idea, but I would advise choosing one or the other of these resources and focusing on it; in any case, you’ll end up selling all your surplus to buy the resource you are missing:
Why produce concrete if you’re going to sell it to buy steel so you can upgrade your AE quickly?
Why produce steel if you’re going to sell it to buy concrete so you can set up a new company quickly?

In my opinion, choosing one resource or the other allows you to pay closer attention to the market price of that resource and sell at the best price.
“Come on, Timmy, if I produce both, I just have to wait until I have enough to make my upgrades, right!?”
"Waiting is bad, m'kay? Sell, Buy, Upgrade, OpTimmyze!"
Do you have money? Invest it in your businesses to generate more.
The guide recommends setting up 6 Co. AE level 5, then 6 Co. AE level 6.
I disagree from an economic build perspective; I’ve done the math, and it turns out it’s more profitable to have:
8 Co. AE level 4
Upgrade all 8 Co. to AE level 5
Build another 1 Co. AE level 5
Repeat the process up to the 12th Company
Upgrade all 12 Co. to AE level 6
Upgrade all 12 Co. to AE level 7
A well located enterprise will minimize the need to relocate it following a lost conflict.
When choosing a location for an enterprise, it is strongly recommended to establish it in a region that provides the highest possible production bonus. This bonus is determined as follows:

Each unique resource increases the bonus by 5% for the resource selected by the country.
In this case, India has chosen iron (see details when hovering over the bonus).
The ruling party’s ideology increases this bonus by an additional 30%.
Recommended regions are available for quick selection:

Lands near names indicate provincial area; a capital city is marked with a star.
If available, select a new location to establish yourself in the capital of the producing country, as it is more likely to be better defended and significantly reduces the risk of having to relocate your business prematurely.

Would you like to discover a new aspect of the game, hire people, and manage them?
Wait until you have your 8th company so you’ll have enough revenue to pay your employees without going into overdraft or reducing growth potential.
If you want to hire, start at the minimum wage to break even, then gradually increase the salary as employee loyalty grows, by mutual agreement.
Use third-party fan sites to help you calculate this balance.
Don’t spend skill points on managing more workers, you’ll need them to increase the number of companies.
The more money you earn, the sooner you’ll be able to invest in your businesses, so avoid unnecessary expenses.
Few random tips to wrap things up:
Reinitiate daily missions that require crafting equipment or eating a steak (if you don’t have the “Eat 2 Foods” quest), it’s too expensive.
Sell the crates (statistically not profitable).
Sell everything else as well; keep only what you need for the next tier, and invest at the right time.
Write serious, funny, or simply entertaining articles in the hope of earning some tips!
Equip yourself with white gear (at max) for missions and wait for the country's or MU's BO to deal damage (damage % bonus).
If you have spare cash, trade (buy and resell).
If the government deems a battle critical, donate !
100po = roughly 1M damage even if it sets you back 2 days!
Don’t spread yourself too thin in production; switching resources or locations is expensive, so calculate your return on investment carefully.
Starting as an eco player doesn't mean you'll never go into combat if you feel like it later on.
Breaking the rules and advice above is fine if that’s what you enjoy, it’s a game, so have fun!
This article was translated from French by DeepL with a few adjustments; please forgive any grammatical errors!
Feel free to leave tips, questions, or suggestions in the comments below!
Timmy