Choosing is a complex operation for me too. Go by director, and expand through enticing reviews, be aware of certain adjectives that describe the kinds of things you like.
Choose something critically acclaimed
Browse through my profile for movie related posts, but many of these films may not be available for streaming unless you have The Criterion Channel.
I'll actually recommend somethings now
The Three Immortal Japanese classics
Ugetsu - Kenji Mizoguchi
Ikiru - Akira Kurasawa
Late Spring or Tokyo Story by Yasujiro Ozu
Explore, and custom make your film experience is the best advice, i for me feel best when i discover it largely on my own, with only reading non-interactively the opinions of others.