TLC has given a second-season pickup to “The Little Couple.”First season averaged 1.1 million viewers and the cabler was encouraged to give it another go-around. Net has ordered 18 episodes — up from 14 in season one — that will be aired in the fall in its 10 p.m. Tuesday timeslot. Skein details the lives of a newly married couple — Bill Klein and Jen Arnold — both of whom are under four feet tall. TLC has had a strong year with “Jon and Kate Plus 8,” “Cake Boss” and “Police Women of Broward County.” “The Little Couple” is produced by LMNO Prods. Eric Schotz is exec producer.