Summarize:

A trench coat isn't only for dressing up. Wearing a trench coat with a plain T-shirt, jeans, and sneakers is a comfortable and fashionable look. You can trade regular jeans for black denim to make the look slightly less casual. Wear a beige trench coat with a white T-shirt, light jeans, and white sneakers. Throw a light gray sweater over the T-shirt in colder weather. This is a great look for mild spring weather. Wear a pair of denim shorts, with a long sleeve button-up, and a medium length trench coat. Roll the cuffs of your shirt over the cuffs of your trench coat. Keep the look very casual by pairing this outfit with a pair of plain sneakers. Slightly dress up the look by wearing pointed-toe flats. Pairing a shirtdress with a medium length trench coat is stylish and classy. Pair a beige trench coat with a black shirtdress and flats for a simple look. Wear a dark trench coat with a patterned dress and ankle boots for a slightly dressier look. Choose a brightly colored trench coat to liven up the look. Sportswear isn't worn only in the gym these days. You can wear nice athletic pants, shirt, and sneakers under a trench coat for a casual and comfortable look. Make sure the sportswear isn't sweat-stained or torn. The sportswear should be nicer than what you would wear for an intense workout at the gym. Wear a matching track suit with a gray trench coat. You can also wear a plain sweater with your athletic pants and sneakers.
Wear a T-shirt and jeans. Pair your coat with denim shorts and a button-up shirt. Try out a shirtdress with your coat. Put on sportswear.