It helps to have a general idea of how you want to win before you start. Your exploration of the map in the first 50 turns or so should give you a good idea of what kind of neighborhood you live in, and then adjust your strategy from there.
For me, I'm usually going for a domination win (based on having advanced units compared to my enemies) or a science win, and those two technology paths are similar. I also want to found my own religion.
For my strateegery, I usually start by researching pottery, building a scout and exploring the map with both my warrior and my scout. Then I build a shrine as soon as I can, followed by a worker.
Regarding the tech tree, I look at the luxuries near my capital, and research what I need to work/harvest those resources (such as calendar, mining, or sailing). Somewhere along the way, I'll research archery, because that's the best way to defend a city early on. Other than that, my tech tree is aimed at philosophy so that I can build the national college as early as possible. The national college is a huge boost to your science output.
To found my religion, I need faith- lots of it. This comes from either having a faith natural wonder (Sinai, Sri Pada, Uluru etc) near a city, being allied with a religious city state, or researching masonry and building Stonehenge.
For social policies, I've been following Tabarnak's 4 cities Tradition opening, filling out the Tradition tree, then going to Rationalism.
I could go a lot deeper, but hopefully this helps for a start.