Might double some aspects, here is my view.
1) you want it for the governer title and either ancestral hall or warlords throne, depending on your plans to play peacfully or war. A second title is rewarded when you finish the t1 building in it. Note that after you adopt a next level government, you can build the next tier of government building in it. T2 for example offers you enhanced spies or the ability to buy units with faith. Again, take a closer look at the godess of the harvest pantheon. I tend to build mostly a campus district in my first city, or less often an encampment district if I want an early general. This triggers the inspiration for the GD. I found my second city and I settle close. More cities = more of everything, no penaltys and defense, especially early. This is anticipating higher difficulty. I want to harvest a food resource in my 2nd citiy to kick it off and build the GD there. If you can, try to put it down and build the diatricts if your 1st and 2nd citiy around it to make benfit of the adhaceny bonus. But it's more important to get a good city location and locking districts early. Don't worry too much about that.
2) I settle close. Defense, district diamonds, shared farm triangles, more cities.
3) You want to do that if you get one, which does not benefit your victory conditions. There are some exceptionally good ones. For me these are the scientists who give +1 for each libary (you will almost never get him on deity), and two who give +2 for universitys. Others just check if tgey would benefit you.
4) If you settle or put a district on a resource you discover later, you'll get the yield.
5) Magnus is very powerful. Pingala too. Read above why. Magnus for chops, pingala for early culture. A horse or sword rush without +2 Magnus is often not doable imo. Magnus synergizes with godess of the harvest. I remind on victorias chopping example here. Armani can secure you an early golden age via first souzerain area score. You can exploit that to get a classical GA nearly everytime you want it if you go for scout(s), armani, settle a natural wonder, build a ship, +4 adjaceny district and some other tricks. This can really take you off, but needs practise and is more advanced stuff.
6) Chose your victory condition and build only the districts you'll need for it. As mentioned, campuses alot. Most often. I can't speak for religous play and holy districts. I feel like religion is weak and I don't go for it except I want a super early relic based CV, which is something you can have a look at in some weeks. For a science victory you need science (yes, really) but you can't neglect culture as you need to advanced to a t3 government, which allows you to build the t3 building in your government district. One ootion let's you spend workers for production in city project, which is needed to speed up your space ship. There are also boosts for science back in the culture tech three, like the +5% for every city state suzerain bonus. For culture you want theatres to get the writers and a mix of archology and artists. You need solid science here too to not getting killed and boni from computers, printing, radio, steel. You also want commercial hubs with markets because trade routes to other civ's give boni to tourism. You need this to if you plan a domination campaign. After some assaults everyone hates you and you can't trade properly,bit you need money to fuel your army. You want science for advanced units and so on. Test it, try it, you'll see what you need. Industrial districts don't pay off often imo,youll need one with a tile adjacent to a river if you want the ruhr valley wonder. Forget about most of the t3 buildings in the districts. They are expansive and rarely pay bavk the investment. A consideration is to buy research labs with big ben, and have a central power hub.