This refined combo of a dark brown crew-neck sweater and khaki dress pants is a must-try ensemble for any modern gentleman. Why not take a more laid-back approach with shoes and complete this outfit with a pair of brown suede desert boots? Can you see how very easy it is to look dapper and stay comfortable come fall, all thanks to getups like this one? And if we're talking outfit ideas for teenage guys, this look looks great on almost any man.