“Don't let yesterday take up too much of today.”

Source: Retribution

The earliest quotes similar to this are presented as unattributed folk wisdom, such as this example from 1959:
As Brother Allen of Newsweek indicated, it has been fun, but don't try to rest on your laurels. Always remember, “YESTERDAY’S HOME-RUN DOESN’T COUNT IN TODAY’S GAME,” and today’s game is well under way.
The quote does not begin to be attributed to Babe Ruth until the 1980s, nearly 30 years after its first appearance.
Disputed
Source: F. N. Abbott, "On Your Marks", in [The Palm, vol lxxix, no. 1 (February 1959), Harry L., Bird (ed.), 1959, Champaign, IL, Alpha Tau Omega, 17, http://hdl.handle.net/2027/uiuc.1744313v0079?urlappend=%3Bseq=19]
Source: https://books.google.com/books?id=cQsKAQAAMAAJ&dq=%22Yesterday%27s+home+runs%22&focus=searchwithinvolume&q=Ruth

The Anatomy of Frustration (1936)

Quoted in National Observer (Silver Spring, Maryland, March 1, 1965).
Other writings

Source: Life, the Truth, and Being Free (2010), p. 36

היום אתה חש מרומם. אל תתן לימות האתמול והמחר להשפיל את רוחך
Hayom ata hash m'romam. Al titen l'ymot ha'etmol v'hamahar lehashpil at ruhekha.
Attributed

Source: Love, Stargirl

Yesterday's Songs
Song lyrics, On the Way to the Sky (1981)