Usually we have the following five ways to say 0 in English.  They are: Oh, Zero, Love, Nought, and Nil.

1. We say “Oh”, when
(I)   after a decimal point
       For example,
       5.02    five point oh two
(II)  in telephone numbers.
       For example,
       64479090    six double four seven nine oh nine oh
(III) in bus No.
       For example,
       Bus No.103    one oh three
(IV) in hotel room numbers
       For example,
       Room 308   three oh eight
(V)  in years
       For example,
      1908    nineteen oh eight
*However, the year 2000 is said the year two thousand;
                  the year 2001 is said two thousand and one;
                  the year 2015 is said two thousand and fifteen or twenty fifteen.

2.  We say “nought”, when “0” is before the decimal point.
     For example,
     0.309   nought point three oh nine

3.  We say “zero”, when
(I)  for the number  
      For example, the number zero
(II) for temperature
      For example, -8℃  eight degrees below zero

4.  We say “nil”, when the “0” comes in the football scores.
     For example,
     3-0   Spain won three nil.

5.  We say “love”, when the “0” comes in the tennis scores.
     For example,
     15-0    The score is fifteen love.