First of all, I respect people’s choice of their gender. If a person asks me to call that person he or she or anything else, I’ll do that. I believe one should have freedom to choose one’s gender as we all are free beings. I respect all genders and I refuse to accept the belief that only two genders exist.
Now, if one doesn’t express one’s choice of gender, I’ll call that person “it”. I believe “it” is a perfect gender-neutral singular pronouns. It can be used for men, women, transgenders, people with no gender, etc. and nobody should be offended by it.
But, still, “it” may cause some problems. For example there may be misunderstandings in some sentences such as this: “If someone asks me to talk to its smartphone, I’ll tell it I don’t want to”. As you see, there may be misunderstanding in some sentences; for example, in mentioned sentence, people may get confused that I talked to the person or to the smartphone.
So I also chose to change some sentences and use “one” instead of person or “it”. This is the way I write my sentences and talk to people. There are some examples in this writing too.
If you see any problem with it or have any ideas, please do contact me.
You can find another ways of calling people gender-neutrally by searching the web. There’s an example on Richard Stallman’s personal website.