Styling a white shirt with blue jeans and a black leather jacket can be a classic and stylish look for men. Here are a few tips to help you pull off this outfit without looking like an undercover cop:

1. Choose the right fit: Make sure your shirt, jeans, and jacket fit properly. This will make the outfit look more polished and less like a costume.
2. Accessorize: Adding accessories can make the outfit look less like a uniform. Try a scarf or a beanie to add some personal style.
3. Mix up the textures: Using different textures can add interest to the outfit. For example, try a cotton shirt, denim jeans, and a leather jacket.
4. Wear different shoes: Avoid wearing black combat boots, which could make you look like a cop. Instead, try a pair of sneakers or Chelsea boots.
5. Layer with a sweater: Adding a sweater underneath the jacket can add dimension to the outfit and make it look less like a uniform.