Neptune is the 6th sense, perceptive, innovation, Kalpak, and rules adhibhautik / metaphysics. It is usually analyzed along with other planets; seldom alone. It heightens the Karakatva of the planets that it is aspecting. For example, Lata Didi has Shukra Neptune very close (Shukra is lagnesh for her too and owns arts along with moon). Also, Dhoni Neptune is opposite to Mars (sports). I have Moon Neptune yuti in the first house (moon is sensing, emotions, dreams, Neptune brings in height to all these things). Neptune at Ascendant degree or the same degree as Ascendant degree in Any house is very significant. Else alone Neptune would not cause many ripples at personal levels. Neptune vibrates to the dates of 7 16 and 25 and to the MEEN rashi (Pisces). So Meen rashi folks and the born with these dates or total birth date adding to 7, Neptune is very imp and the house Neptune is in also imp. (Once I was analyzing a horoscope of a girl with Venus in Taurus (Vrishabh) and Neptune bang opposite it. I questioned if she sung well or had some other art - She indeed was a very good singer. I thought she would do well in something like Indian Idol or similar programs in 2007 when Guru was in Scorpio. She didn't try but got internal company award/recognition etc in the internal organization programs! As Shukra was in the 5th house Raajyogkarak for Makar lagna -- it further underscored this ability.)
Needless to say, Neptune dominated people are very good in reading body language, reading thoughts and sensing overall the mood of the surrounding. Understand the pauses and gaps in the words or sentences better!