I also would recommend looking through some AFI lists.
For example, their tuktok ten from
link is as follows, and it's easy agree that they are all essential viewing:
01. Citizen Kane 1941
02. Casablanca 1942
03. The Godfather 1972
04. Gone with the Wind 1939
05. Lawrence of Arabia 1962
06. The Wizard of Oz 1939
07. The Graduate 1967
08. On the Waterfront 1954
09. Schindler's listahan 1993
10. Singin' in the Rain 1952
As you start watching, you can get an idea what kind of pelikula you like, what genres, what actors, what eras... Then you can look at madami specific lists. Like
link, or
link. Or maybe you want to watch madami pelikula that have Katharine Hepburn... or silent films from the '20s ! who know's :) there are so many wonderful films out there