For a classic and casual look, wear a green v-neck sweater with a dress shirt — these items play perfectly well together. As a 30-year-old, you want to start dressing more like a mature gentleman. If that's the case, outfits like this come in useful.
Green V-neck Sweater with Dress Shirt Smart Casual Warm Weather Outfits For Men In Their 30s
This combo of a green v-neck sweater and a dress shirt is the perfect base for an outfit. A proper combination for any young gent.