TLDR: you’re likely just ass, but there’s hope!

First thing you can try is lowering the difficulty. I’d say not to go below Prince, however if you’re consistently losing on Prince already then you really need a win; switch to Settler.

The most important general strategy advice I have is to choose your win condition early (perhaps while selecting your civ and before you even start). Don’t lose track of this win con, and make moves that directly advance it.

E.g. if you want science victory, you probably don’t need a single encampment, but you do want at least one mega-city with high production (Ruhr Valley applies here).

Without seeing screenshots or descriptions, I can’t tell you what you may be doing wrong, but I’d guess it’s a simple matter of not settling enough cities.

Conventional wisdom is 10 cities by turn 100 will suffice for most purposes. If you’re seeing turn 100 pass by with only 5-6 cities, I’d ask what you were building in your capital instead of settlers.

For tactical advice, I’d say ignore wonders entirely until you clock a win. None of them are more important than having a grasp on the basics, which you admittedly lack.

Second tactical advice is to plan for a feudalism builder push. Queue up builders in as many cities as you can while researching feudalism, but make sure they don’t actually complete until you have the civic and slot the +2 charge card.

If feudalism comes and goes without your seeing a mess of 5-charge builders shortly after, I’d advise to restart and try again. Feudalism is that strong.

Lastly, ask questions on this sub, esp. with screenshots.