The Lurian barfly Morn was named in tribute for the Cheers character Norm
Ep. 1 Emissary Morn the local bar fly at Quark bar was said to be the most talkative person on the station but was never heard speaking on screen
Ep. 1 Emissary Deep Space Nine was aired to compete with Warner Brother Babylon 5 another Sci-Fi Series set on a space station. Some people even accuse Paramount of stealing the idea from Warner Brother
Ep. 3 A Man Alone The planet "Alderaan" is listed as a recent place visited by a murder victim. (Alderaan is the planet that's destroyed by the Death Star in Star Wars A New Hope.)
Ep. 24 Body Parts Max Grodénchik who plays Rom also plays the First Grand Nagus Gint