The key to having soft and smooth lips is to keep it hydrated. The skin that we have on our lips is different from most of our skin, it is actually thinner and is lined with mucous membrane which explains its pinkish color. Mucous membrane also lacks keratin (a tough protective layer that keeps our skin from drying) so it has to be moistened.
Since the skin on our lips is thin and fragile, I don't really recommend scrubbing or exfoliating it as this will only make your lips chap more. A simple lip care routine like lip balm and sunscreen is enough.
If you have very dry or chapped lips, make sure to slather on some lip balm or petroleum jelly before going to bed and you'll be good the next day. Also, NEVER lick your lips as this may cause your lips to chap even more. Saliva contains acid that helps break down food and when it dries out, it dehydrates our lips even more.
So make it a habit to moisturize lips by keeping a handy lip balm in your purse to make sure you'll have soft and kissable lips all through out the day!
Anj :)