WESTFIELD — Know your audience. Play to them with a program that will interest them, and you’ll fill seats. That’s what David Wroe, music director and conductor of the New Jersey Festival Orchestra, has found to be true. The New Jersey Festival Orchestra (NJFO)’s yearly New Year’s Eve concert was held again at Westfield High School to almost 600 fans. The Sunday night program featured songs from famed composers — Cole Porter, Irving Berlin, George Gershwin, Richard Rodgers and Leonard Bernstein. Repeat composers and repeat guest performers were added to the draw.