How can I be a good SIL?

As someone whose family forgets that I exist here’s what I would want and what I want for my child:

Take an interest in me. Even if the only thing you can remember is my hobby xyz, talk about it with me and ask about it occasionally.

Remember my kids. Buy calendar in January and put everybody’s birthdays on it so it’s not just social media reminding you. Birthday cards can be bought at dollar stores, and stamps are still somewhat reasonable. In the US it cost less than a dollar to send a birthday card but it can be the most thoughtful thing somebody gets.

Don’t help isolate me. For example my family is really into a sport. I don’t care about it. I can’t count how many times I’ve been left out of conversations, gatherings and have generally made to feel like an outsider because I don’t care about somebody throwing a ball. If you see she has been silent all night, ask her a question about something you know she’s into.