This casual pairing of a white and green long sleeve t-shirt and chinos is super easy to throw together without a second thought, helping you look dapper and prepared for anything without spending a ton of time combing through your wardrobe. A pair of multi colored canvas low top sneakers looks perfect here. Keep this look in mind when warmer days are here, and rest assured, you'll save a lot of time brainstorming for a look on more than one morning. When it comes to casual style tips for 20-year-olds, this outfit looks great on most guys.