仔细：careful, normal amount 细心：careful plus a little patience 小心：careful (watch out), maybe sometimes too careful 详细：very detailed But really depending on the context. The first three are very similar, I think you can use them all in the same way.

仔细：careful(ly),don't overlook or make mistakes,usually use it to describe doing something carefully eg:看仔细一点。 细心：thoughtful，considerate， usually use it to describe personality or character,or the way someone do things eg:他做事很细心。 小心：watch out ,be aware of dangers,usually used as a phrase or verb eg:小心！ or小心那辆车！ 详细：complete and detailed ,usually used to describe written content or spoken words eg:详细的解释 ，详细的说明 you raised a great question.em,it is hard for you to distinguish them as words, maybe you put them into specific usages. better gather some examples and feel the difference. i wish my answer can help you a little bit