Not really a "conversation starter" but usually japanese ask for their age as well as how should they adress each other.
If someone is older for example, the younger one should use polite speech. But at the same time, they also ask directly if they should use polite speech or not, if they should drop honorific or not, etc.
Those are not really conversation staters but people often try to figure the "distance" they should take when talking to each other. Some japanese can't drop polite speech for example and it's better to stick to polite speech in those case.
Other than that, native will often ask you why you're learning japanese. So it can useful to prepare some sentences that. After that, it's really random, so nothing will really help except... knowing more x)
hey just wondering what are some good conversation starters for Japanese?