Religion is the one and only dicey subject that is tipping over the boiling point over small issues. So if you want to stay polite, try avoiding debates and discussions that involve religion. Don't take any stand as to which religion you prefer over which, and the like, you get my point? Also, when you visit a temple, make sure you're wearing "decent" clothes, that is, your body is covered in all the right places. To be safe, carry a shrug or a stole with you. Apart from this, just follow the regular human to human polite manners and you should be good to go! Just be wary when it comes to religious matters.