After your shower or bath stand in front of a mirror with a good light.
Look for any visual changes in your breasts. Please note the right breast is slightly larger than the left - this is not uncommon.
Note any change in the following: size, shape, level of nipples, obvious lump, skin colour, dimpling or tethering, change in skin of the nipple.
Lift your arms above your head to see whether there is any dimpling or tethering of the skin.