If the fleshy mounts and flat plains are the topography of your hand, the lines are the roads that cross it as you journey through life. Get familiar with the major freeways that mark just about everyone's hand, even if you don't see them change much, because they will help you as reference points for the mounts. Just as you might say, "Hey, didn't there used to be a fast food joint on this corner?" on your familiar drive to work, seeing things pop up near the lines on your palm can be noticeable and more easy to watch. Lines do change, and for some people they may deepen, lengthen, or lighten and become less noticeable more quickly than for others. Keep your eyes on the road with these major lines on the hand:
Heart line: Starting from the top of your hand, the heart line is the highest major line most people have. It starts at the percussive side of the hand, travels through the top middle area of the palm, and terminates under or within one of the mounts. The heart line has to do with your love life, not only the way you seek and find love, but the process of dating and marriage as a journey rather than a destination. Some people have the head and heart line joined as one, which is called a simian crease.
Head line: Under the heart line, most people who don't have lines fused as a simian crease have a head line crossing the middle of the palm, starting near the webbing of the thumb and pointer finger, and traveling to terminate somewhere in the middle of the palm. The head line is your intellectualism, the way you think, and the way you think about thinking. The head line can hold clues about how you interpret the world.
Life line: The life line also starts near the webbing between the thumb and pointer finger and swoops wide around the thumb to terminate somewhere in the middle of the palm or at the bottom near the wrist. Your life line represents your journey through life including health, travel, and living situation.
Destiny line: Many people have a rising line of Saturn that crosses the very middle of the palm vertically, starting somewhere near the bottom of the palm and rising up to terminate somewhere near your middle finger, or at least pointing vaguely in that direction from the middle of the palm. Don't freak out if you don't have a destiny line, as some people do not. This line, if present, has the same associations as the Saturn mount and finger, and often has to do with career and money.
Jupiter line: Some people have a line of Jupiter rising vertically underneath the pointer finger, having to do with leadership roles and other associations with the Jupiter mount and finger.
Apollo line: Some people have a rising line of Apollo vertically under the ring finger, having to do with the way they seek recognition and creative influence in the world, along with other Apollo mount and finger associations.
Mercury line: Some people have a rising line of Mercury vertically under the pinkie finger, having to do with communications with others, roles in their families, and helping others in their community, along with other Mercury mount and finger associations.
From Palmistry Every Day, by Alexandra Chauran.