Even if your office attire does not require wearing a suit, or you just do not like wearing suits, you can still look sharp at the office. The key is to look for clothes with some structure. When we think about a suit what are its key elements? Collar, structure, sleeves, neutral color and class styling. So when you do not want to wear a suit, make sure your outfit has the feel of a suit in a way, so that you look conservative enough to blend in.
Collar: Look for clothes that have a collar or higher neckline in appearance, or even the feel of a collar.
Structure: Your clothes need to be made of fabrics with some weight, not light and airy, as they convey more authority. A set in sleeve rather than a raglan sleeve will always appear more formal.
Sleeves: If men are wearing suits and ties, women need to cover the tops of their arms. Look for garments that have sleeves built in.
Neutral Colors: Wear more neutrals rather than really bright colors. You can still wear color, but opt for solids over patterns as they appear more business like and team back with neutrals.
Classic Styling: You do not have to wear a matching suit, think about a jacket and pants or skirt that work together, but are not a formal suit. This can work well for many who have a more relaxed personal style and feel suits are too conservative.
Inspiration from Pinterest.