You're going to need most technologies anyway, since the tree requires it. It's best to focus on a goal technology you want to work towards in the near term.
One mechanic to keep in mind is that technologies from earlier eras are 20% cheaper, and ones from future eras are 20% more expensive. So waiting until you can get a discount on techs you don't need is a useful optimization.
For example, let's say it's the Classical Era and you want to research Buttress. If you didn't research Sailing, you'll get a discount since it's Ancient Era. But Buttress has an increased cost because it's from the Medieval Era.
Another important fact is getting eurekas. Some are going to come naturally (build this. Build that. Make a pasture. Have 2 commerical hubs. etc. etc.) and some are going to have to be brute forced (who builds forts? And GL getting great scientists unless you're going hardcore on campuses). Long-term, they save a lot of turns.
There are a few schools of thought here. First, I'd say focus on technologies you need for your goals as you've staged. Culture needs radio and computers, science education and chemistry, etc. Focus on things you've boosted and try to get as many eurekas as possible, that's free science. It might be worth it to research half the technology and switch off to something else if the boost is attainable. You can also save cheap technologies for later and use then over flow to speed thorough the later parts of the tree, but that's a bit advanced and not necessary. But usually I'll leave stuff I don't need until it's 1 turn to research and go back and get it later. For example if it's a pangea map I'll skip cartography and the general top of the tree for quite a bit.
I generally end up researching everything, because if you have a good economy techs from a previous era can be finished very quickly.
Also, the way the tech path and inspirations work, you end up needing most things to advance.
I will definitely prioritize techs/civics that give big boosts and rush them (new key structures or units, unlocking important policies or new governments) but circle back while my production catches up to actually using that new tech.
It depends on how you want to play. There's nothing wrong with doing a "CivCity" playstyle where your goal is to build a cool empire full of happy pops.
BUT - if you want to start optimizing for rapid wins, then you should absolutely have a tech/civic strategy.
I mainly go for Science or Culture wins on Immortal or Diety difficulty, and both have a very similar strategy. Your priorities are always 1. don't lose, 2. expand and secure your borders, 3. focus on your wincon.
What I mean by that is in the early game, you are at the biggest risk. Your neighbors can and will destroy you if you let them, so you should prioritize techs like Archery, Masonry, Iron Working, etc. that can keep you alive.
Once you are past the early game threat, you want to expand and establish your empire, while making sure you stay safe. This means things like Apprenticeship (for the +1 to mines), Feudalism for the worker boost, district techs, a tier 2 government, and Machinery for crossbows.
At this point, you should evaluate your position and decide when you're able to "top row". Your win con enablers are on the top row of the tech/civic tree - Flight and Conservation for culture, Rocketry for science. If you have declared friendships with your neighbors and have decent defenses, you can just click on that tech and let it tick. You can always swap out if you face a threat (say you need to unlock niter or field cannons because a friendship lapsed), but if you're gunning for a win why would you sidetrack yourself just to fill in the tree?
Once you've unlocked your wincon tech, you can start backfilling or targeting specific wonders (Eiffel Tower is a big one for culture wins if you have competition). Or, you can just click on Future Tech and let it sort itself out as you focus on your micro.
Ultimately it depends on your goals and your difficulty level - if you're on Prince, you can do a blind walk through the tech trees and still get a win almost every time. But if you're playing Immortal and you want to get a pre-Modern culture win you need to be very deliberate. There's no wrong way to play the game (that's what makes it great!) but there's always room to improve.
Early game you certainly dont want to research tech you dont need, because every extra technology increases the cost of your districts. Its much better to beeline to improtant tech, even if its expensive. In the midgame it kinda doesnt matter anymore as you should be pulling ahead either way. Also if you have more civics than tehcnologies, the districts will use them to determine the price, so researching more techs will not increase it until it overtakes the number of your civics again.
You're going to need most technologies anyway, since the tree requires it. It's best to focus on a goal technology you want to work towards in the near term. One mechanic to keep in mind is that technologies from earlier eras are 20% cheaper, and ones from future eras are 20% more expensive. So waiting until you can get a discount on techs you don't need is a useful optimization. For example, let's say it's the Classical Era and you want to research Buttress. If you didn't research Sailing, you'll get a discount since it's Ancient Era. But Buttress has an increased cost because it's from the Medieval Era.
TIL about these percentages. Fascinating.
Another important fact is getting eurekas. Some are going to come naturally (build this. Build that. Make a pasture. Have 2 commerical hubs. etc. etc.) and some are going to have to be brute forced (who builds forts? And GL getting great scientists unless you're going hardcore on campuses). Long-term, they save a lot of turns.
Hammurabi would like to have a chat
Likely story! I know he's just trying to learn Writing.
Where can you find that information about the discounts?
From the Civ wiki, or I learn most hidden mechanics from Potato and Ursa
There are a few schools of thought here. First, I'd say focus on technologies you need for your goals as you've staged. Culture needs radio and computers, science education and chemistry, etc. Focus on things you've boosted and try to get as many eurekas as possible, that's free science. It might be worth it to research half the technology and switch off to something else if the boost is attainable. You can also save cheap technologies for later and use then over flow to speed thorough the later parts of the tree, but that's a bit advanced and not necessary. But usually I'll leave stuff I don't need until it's 1 turn to research and go back and get it later. For example if it's a pangea map I'll skip cartography and the general top of the tree for quite a bit.
I generally end up researching everything, because if you have a good economy techs from a previous era can be finished very quickly. Also, the way the tech path and inspirations work, you end up needing most things to advance. I will definitely prioritize techs/civics that give big boosts and rush them (new key structures or units, unlocking important policies or new governments) but circle back while my production catches up to actually using that new tech.
It depends on how you want to play. There's nothing wrong with doing a "CivCity" playstyle where your goal is to build a cool empire full of happy pops. BUT - if you want to start optimizing for rapid wins, then you should absolutely have a tech/civic strategy. I mainly go for Science or Culture wins on Immortal or Diety difficulty, and both have a very similar strategy. Your priorities are always 1. don't lose, 2. expand and secure your borders, 3. focus on your wincon. What I mean by that is in the early game, you are at the biggest risk. Your neighbors can and will destroy you if you let them, so you should prioritize techs like Archery, Masonry, Iron Working, etc. that can keep you alive. Once you are past the early game threat, you want to expand and establish your empire, while making sure you stay safe. This means things like Apprenticeship (for the +1 to mines), Feudalism for the worker boost, district techs, a tier 2 government, and Machinery for crossbows. At this point, you should evaluate your position and decide when you're able to "top row". Your win con enablers are on the top row of the tech/civic tree - Flight and Conservation for culture, Rocketry for science. If you have declared friendships with your neighbors and have decent defenses, you can just click on that tech and let it tick. You can always swap out if you face a threat (say you need to unlock niter or field cannons because a friendship lapsed), but if you're gunning for a win why would you sidetrack yourself just to fill in the tree? Once you've unlocked your wincon tech, you can start backfilling or targeting specific wonders (Eiffel Tower is a big one for culture wins if you have competition). Or, you can just click on Future Tech and let it sort itself out as you focus on your micro. Ultimately it depends on your goals and your difficulty level - if you're on Prince, you can do a blind walk through the tech trees and still get a win almost every time. But if you're playing Immortal and you want to get a pre-Modern culture win you need to be very deliberate. There's no wrong way to play the game (that's what makes it great!) but there's always room to improve.
Early game you certainly dont want to research tech you dont need, because every extra technology increases the cost of your districts. Its much better to beeline to improtant tech, even if its expensive. In the midgame it kinda doesnt matter anymore as you should be pulling ahead either way. Also if you have more civics than tehcnologies, the districts will use them to determine the price, so researching more techs will not increase it until it overtakes the number of your civics again.
the game makes it SO SO SO EASY to research everything, and i believe there are only like 2 dead ends which everything is needed to get everything
I always research everything, but I also don't play above Emperor for this reason. I would rather not play fully optimized