How I talk about gods
When I discuss the concept of gods with other people, I try to choose my language very carefully. I may being with a very generic description of gods (plural), but then, as they begin attributing qualities to their god, I will start referring to their god specifically as their god, not the god. I do this for several different reasons.
To Not Lend Credibility
When you use the same language someone uses regarding their beliefs you run the risk of giving them the impression you endorse their beliefs. For example, if a person refers to an ethnic group using a slur, and you refer to the group with the same slur, they will probably get the impression that you also hate the ethic group.
Monotheists believe that their god is the only real god, and that all other gods are imaginary, and use language to this effect. Their god is capital "God" and all other gods are lowercase "god." Since I don't want to give them the impression that I believe their god is superior or even real, I make an effort to not adopt their language and always refer to their god as a lowercase "god." I won't ask, "do you believe in God?" but rather, "do you believe in any gods?" If they make it clear to me they are a monotheist, I may ask, "which god do you believe in?" or "what is your god's name?" If they make it clear to me that they refer to their god as "God," I won't ask a question like, "do you think that's what God wants?" but rather, "do you think that's what your god wants?"
World-traveled Believers who are aware people believe in all sorts of different gods will understand the utility of this, but believers who are quite insulated (which seems to be most of them) tend to respond by saying something like, "he's not my god, he's everyone's god, including yours!" When responding to this, I try to explain my other reasons for why I speak about gods generically.
Believers often confuse their gods without even knowing it. When Catholics and Protestants talk, they have the impression that they're both talking about, "God," but, in reality, they are talking about two different ideas. This is because Catholics and Protestants have mutually exclusive ideas for what their god wants, so they can't be the same god.
Of course, all monotheistic religions believe that their god is the only god and also the god of every person on Earth, but, since they all believe in different gods, they can't all be right. To help them understand this, I may ask them, "when you say 'God,' are you referring to the Muslim god, or the god in which you believe?" Here, "Muslim god" is a placeholder that can be swapped out with whichever unnamed god they are likely to hate the most. When they clarify that they're not referring to anyone else's god but their own, I explain to them that this is why I say, "your god," and not "God."
To Not Play Favorites
Those who worship a god without a name, including anyone who worships a god based on the Abrahamic faiths, tend to refer to their god as "God," and everyone else's as "god." Although I don't personally believe in any gods or even respect any god beliefs, I do respect everyone's right to hold god beliefs. Because of this, I try to not play favorites with any god belief. If I were to refer to the Jewish god as "God," but the Christian god as "god," I would be playing favorites by implying the Jewish god is more proper than the Christian god. I also can't refer to them all as "God," since they're each described in contradictory ways, so it would be irrational to do so. Therefore, I use language in which all gods are considered lowercase "gods." I will still use the proper case when referring to a god by their name, for example "Zeus."
To Use Proper Grammar
Consider this passage from the King James translation of the Book of Genesis, "In the beginning God created the heaven and the earth. (1:1)" The capitalization seen here is not correct. "God" is a title, not a name, and titles should only be capitalized when they're applied to a specific person. It is correct to capitalize the title in this sentence, "I saw a painting of President George Washington," because it refers to a specific president, but you would not capitalize it in this sentence, "I saw the president." You will sometimes see the word capitalized unnecessarily, like, "The President is doing great!" but this is usually a result of political propaganda and not proper English.
English has a lot of archaic traditional rules, one of which says that you should always capitalize the word "god" when referring to the Christian god, as well as any pronouns associated with it. However, this rule was not created for clarity or consistency, it was a special rule given solely to the Christian god by Christian grammarians. As I do not like to play favorites, I will not abide by such a one-sided inconsistent rule.