The best way to find skin cancer before it becomes a serious problem is by checking your skin regularly. Freckles, moles, and birthmarks on your skin can be normal, but some may develop into skin cancer. It is important to look for changes in these spots or the appearance of new spots when checking your skin. See more on skin self-examination here: Screening and Early Detection. It is also a good idea to talk to your doctor about your level of risk and for advice on early detection.