What can developers do to assist in automation testing?

The company I work for is starting a new web application, and I have requested that front end developers make this application Automation Friendly.

The previous application was using the react framework, very few elements had unique ID's (or any unique identifier at all). This time around, I have asked the developers to include a custom data attribute, specifically for automation.

I am looking for anyone who may have experience in this kind of situation.

1. What have you asked your developers to do to assist in automation?
2. Are there any standards, or guidelines for naming elements in an application to suit Selenium automation?
3. are custom data attributes the best way to go? are there other options?

Any advice/guidance would be greatly appreciated!