This casual pairing of a navy long sleeve shirt and skinny jeans is extremely easy to put together in no time flat, helping you look dapper and ready for anything without spending a ton of time going through your closet. You can take a classic approach with shoes and add black leather chelsea boots to your ensemble. While it can be a bit difficult at times to stay on-trend in cold temperatures, it's ensembles like this that prove it's totally possible. All in all, a perfect demonstration of smart casual fashion for gents in their 20s.