Doing Exams. After your next exam at the physician begin regular exams and feel what's there. This would be considered your normal. You will learn this very well. What you are looking for is something new and different. Therefore, you don't have to be an expert in breast to do exams. It is very easy to feel something new.
Get help. Have your doctor or his nurse show you how. This is your baseline normal. Watch for changes. Do screening mammo if appropriate.
Focus on YOUR normal. Focus on learning what's normal for you and your body. Then if there's something different or drawing your attention particularly if it's persistent then contact your doctor and let them evaluate.
Know your normal. The main goal of a breast self exam (bse) is to get to know what your normal lumps feel like. You should do this every month about 10 days after the start of your period. Once you are familiar with your unique lumpiness, then feeling something abnormal is easy. It takes practice and diligence. A significant other can be helpful as well if you are not comfortable with your body.