Why not pair a navy and white check long sleeve shirt with navy chinos? These pieces are very comfortable and look good combined together. Introduce beige suede loafers to the mix to avoid looking too casual. This combo is a tested option if you're hunting for a great, season-appropriate combo. A great combo to demonstrate the world your maturity as a 30-something man.
This casual combo of a navy and white check long sleeve shirt and navy chinos can go different ways according to the way you style it out. Introduce a pair of red suede driving shoes to the mix and the whole getup will come together. Stick with this one if you're looking for a solid summertime look. And if we're talking style tips for gentlemen in their 30s, this combo looks cool on most.