Look for projects where the director, casting director, producer, and director of photography are all different people.
If the same person who is more than two positions, it probably means the production will not run efficiently.
Start looking for paid projects.
If someone is willing to pay and are upfront about it, then it will seem more legitimate. Also if someone cares enough about their project, they will invest in it to make sure it is done correctly.
SAG-AFTRA waivers and projects will ensure you receive higher paid work.
Just make sure you do not jump into becoming SAG-AFTRA too early or you could potentially lose out on meeting up and coming industry people and non-union paid work.