"Break" refers to how the cuff of your pant leg drapes over your shoe. There are three main options for how your pants should break.
Advice: A slight break is ideal. The look is modern, but not too trendy.
"Leg opening" refers to how tight the pants fit around your ankles.
Advice: Tapered or straight are your best bets here, as both are flattering cuts that will work for most men. Avoid boot cut unless you're working on a construction site and are actually wearing large heavy boots.
BONUS: Suspenders have gone in and out of fashion throughout the 20th century. Today they're quite rare, but can appeal to the man looking for a vintage-inspired ensemble.
Advice: A timeless, classic belt is the way to go for both formal and casual wear. Suspenders look old-fashioned and more like a costume. One important thing to remember: Belts and suspenders should never be worn together.