Here are my rules for wearing a blazer with jeans:
1. Dress for the Weather
Because it was cold I decided to pair this blazer with a heattech turtleneck to stay warm while looking stylish. You could also add in a wool or cashmere scarf either plain or a very subtle pattern to eliminate the need for a heavier coat and makes for a great autumnal look. If it's warm outside, I would pair this jacket with a plain t-shirt. A good rule of thumb is to keep your shirt layer completely plain. Go with white or black to make your jacket be the stand out piece.
2. Choose a Sports Jacket
Don't ever break up a suit for this casual look. The jacket will be too formal to wear with jeans. Stick with a sports jacket. Look for casual details like 2 buttons and elbow patches.
3. Color Contrast
Your sports jacket shouldn't color match your pants. A color contrast helps make the outfit pop. My black turtleneck, grey sports jacket really stand out against white jeans. Likewise, if you go with dark denim, try a lighter colored coat.
4. Keep Everything Else Sharp Casual
- Shirt: I see people make the mistake of then pairing their jacket with a formal shirt and distressed jeans. Go with a plain turtleneck, t-shirt, nothing crazy.
- Jeans: I'm not a believer in "don't wear white after Labor Day" and I liked to pair this look with a pair of skinny white jeans. They add sophistication to the outfit without going too casual and pair nicely with the jacket. Make sure your jeans are a little more formal, meaning no ripped or distressed jeans. You can't go wrong with well-fitted dark jeans.
- Shoes: I chose to go with these leather Gucci Chelsea boots. You could also wear this look with plain white sneakers, such as Common Projects or something similar. You can experiment with different textures, such as leather or suede. Leather oxfords or loafers are also a good choice.
