Add classes to GF form fields; these are the most commonly used, but look at the others also.
These are deprecated with Gravity Forms 2.5 and higher.
Halves (2 Columns)
gf_left_half | gf_right_half
Thirds (3 Columns)
gf_left_third | gf_middle_third | gf_right_third
Inline (Fluid One Line)
gf_list_2col | gf_list_3col | gf_list_4col | gf_list_5col | gf_list_inline