ALONE AT LAST!
Credit: LA Times Crossword
Sylvia Bursztyn and Barry Tunick  (#1-8)

The anwers to the clues below will have something in common.

1. July 4 in the USA
2. Celebrity introduction, perhaps
3. Silver owner
4. Robinson Crusoe or #3 above
5. One behind the other in line
6. Certain diamonds
7. Uncontracted writing
8. Gave special attention to
9. Unhappy couple, perhaps
10. "The loneliest number" in song by Three-Dog Night
11. Epic western novel by Larry McMurtry
12. Famous Greta Garbo quote
13. Not bound by conventions or obligations
14. Not married or in a relationship (two answers)
15. Ray Orbison classic

Answers:

1. Independence Day
2. "The one and only"
3. The Lone Ranger
4. Sole survivor
5. Single file
6. Solitaires
7. Freelance
8. Singled out
9. Alone together
10. One Is the Loneliest Number
11. Lonesome Dove 
12. "I want to be alone."
13. Free spirit
14. Unattached or single
15. "Only the Lonely"