zodiac = {'aries': 'compatible with Gemini, Sagittarius, Leo.   business person.',##There are 12 keys with values that are each of the 12 zodiac signs.  The values of each of the keys is for best romantic picks and jobs.
          'leo': 'compatible with Sagittarius, Aries, Gemini.   performer.',##I tried to arrange each key at beginning of line to look better.
          'sagittarius': 'compatible with Aries, Aquarius, Leo.   animal training.',##shortened some of the values from previously
          'cancer': 'compatible with Taurus, Scorpio, Virgo.  Social work.',
          'scorpio': 'compatible with Cancer, Capricorn, Pisces.   detectives.',
          'pisces': 'compatible with Scorpio, Cancer, Capricorn.   natural artists.',
          'taurus': 'compatible with Cancer, Capricorn, Pisces.   great teacher.',
          'virgo': 'compatible with Taurus, Cancer, Capricorn.  Great television critics.',
          'capricorn': 'compatible with Taurus, Pisces, Virgo.   good managers.',
          'gemini': 'compatible with Pisces, Virgo, Scorpio.  Architects.',
          'libra': 'compatible with Pisces, Cancer, Taurus.   diplomat.',
          'aquarius': 'compatible with Sagittarius, Libra, Gemini.  Scientist or inventor.',}

while True:##I placed everything in a while loop like you suggested to make the whole thing better.
       print('Hello and welcome to the zodiac compatibility and career wizard')##This is the initial welcome to the user
       print('These are the zodiac signs.')##lets user know list of keys are only ones
       for k in zodiac.keys():##prints keys
        print(k)
       print('Enter Your Sign: (blank to quit)')##This gives the user a chance to quit
       sign = input()##sign is assigned the value given by the user
       if sign == '':##if they press retun with a blank it ends
           break

       if sign in zodiac:##Checks to see if sign in dictionary data, I did not add a way to add a key because there are no more zodiac signs.
         print(zodiac[sign])##this prints the information for the user zodiac
       else:
        print('I do not have  information for ' + sign)##error message
print('Thank you I hope you enjoyed the information!')##goodbye message to the user