The combo of a white print long sleeve t-shirt and navy chinos makes this a cool casual menswear style. A pair of white canvas low top sneakers can integrate smoothly within plenty of ensembles. As the weather starts getting warmer, it's time to get rid of those bulky winter layers and opt for something lighter, like this ensemble here. And if we're talking casual outfit ideas for men in their 30s, this combination looks good on most gents.