Here is an example of a basic suit. It's simple yet classy. Do not forget the tie clip! A floppy tie is enough to bring your whole look down. Also, a fitted shirt is key. You don't want to look like you are swimming in your clothes.
-- Inspiration -- -- -- Brown jacket brown bow tie dark denim and white shirt with the white pocket square. That would be a great way to make denim look not so casual. Of course the black dress pants and black bow tie as shown here looks ok too