If you feel more confident wearing something functional, you'll love this on-trend combination of a red v-neck sweater and navy jeans. Dial down the casualness of this ensemble by finishing with monks. This one is a viable idea if you're on the lookout for a cool summer-to-fall outfit. As a gent in his 30s, you want to start dressing more professionally. In this case, combos like this come in very handy.