I'm by no means an expert but for religious victories you're obviously going to want to be generating a ton of faith. If you can get a pantheon that generates passive faith from features within your empire or from holy site adjacency then you'll be off and running
For founder belief, often Pilgrimmage is the best option as it gives you +2 faith per city with your religion. As you convert more and more cities this will really help scale your faith income to help offset higher costs of religious units as you purchase more of them.
The best worship building imo is mosques because it will give your missionaries and apostles +1 charge which is massive, especially for apostles.
For enhancer belief, I find Holy Order to be most useful as it significantly cuts the purchase price of your religious units making you able to spam them more freely.
For general strategy, use missionaries to convert your own cities and other civs without an established religion to help generate more religious pressure for cheap. Save your apostles to convert lands under another religion and especially for holy cities. If you can use your apostles to fight their religious units then you will get free pressure and reduce their pressure. If your apostle is injured it will spread your faith less effectively but you can always heal back up on your holy sites if it's a reasonable distance away.
Besides that, get these wonders when available: Mahabodi Temple (great for evangelizing your religion with the two free apostles) and Hagia Sofia (even more charges for your units). If you get a Golden Age then of course Exodus of the Evangelists is amazing. Theocracy is also very helpful if you're all in on religion.
Using all of these may end up being overkill depending upon the difficulty but the computer doesn't tend to beeline for any of these beliefs or wonders in king or under so you should be able to pick most of them if you're really focusing religion.
