One, we need to take care of ourselves. There is no need for a fad diet (they don't work) but we should try and eat healthy. Sometimes, we don't have time to cook and we may not have the funds or access to organic goodies, but eating a balanced diet is so crucial to a healthy body, as well as glowing skin and gorgeous hair. Drink lots of water. Exercise according to your ability and your interest (you don't have to be lifting all the time, but swimming, walking, dance class, kickboxing class, Pilates DVD, all of that counts). Exercise gives shape and tone and also is good for preserving health and keeping us young. Of course, hygiene goes without saying and it's good to at least keep our hair trimmed every couple of months. Basic steps like these go a long way.
Two, we need to figure out what style works for us. Some women rock long hair, others short. Some like it straight, others curly. Some want crazy colors, others are more neutral. As long as it's healthy and you feel good, who cares (sometimes, even employers don't!)? Same goes for makeup (hell, if you don't like makeup, don't wear it!). As for clothes, as long as they're seasonably appropriate (meaning, you're not wearing short shorts in a blizzard), clean, and suit you (your style, your shape, your culture if applicable, etc), it doesn't matter! OK, it does, but you can still find appropriate clothing for various occasions that reflects who you are! Find what you like and rock it.
Third, all of the above means nothing if we don't try to develop inner beauty. There is a quiet confidence present in the sexiest of ladies. A woman may not be conventionally attractive yet can stun an entire room with her smile, her laugh, and her impeccable inner strength. There are a couple secrets to achieving this. One, we must develop our skills and talents, knowing we have something valuable to contribute to the world (and acting accordingly). Two, we must be humble and gracious to all those we meet. Now, humility isn't about beating ourselves up. To be humble means to not act either less or more than you are (trust me, still working on it). It means controlling impulses and only acting defensively if there is something worthy to defend (such as our lives or that of someone else's, also principles). Three, we must love other people. While many of us dream of romance, we sometimes forget the love of our family and our friends. In addition, we forget that each person we meet is just another person and should be treated with respect (which comes out of love. Not "warm and fuzzy love" but a desire for good for other people).
Finally ladies, we must love ourselves. If we don't love ourselves, there is no point in trying to improve ourselves. If we don't love ourselves, we can't love other people. For the Catholic/other Christian ladies reading this, Jesus even said, "Love your neighbor as yourself." Well, if you can't love yourself, you're going to do a shitty job of loving your neighbor!!! My religion teaches that we were made in the image and likeness of a benevolent deity. By nature, we ARE beautiful. Let's start believing it!