I also would recommend looking through some AFI lists.
For example, their top, boven 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 lijst 1993
10. Singin' in the Rain 1952
As u start watching, u can get an idea what kind of films u like, what genres, what actors, what eras... Then u can look at meer specific lists. Like
link, of
link. of maybe u want to watch meer films that have Katharine Hepburn... of silent films from the '20s ! who know's :) there are so many wonderful films out there