1) Like the book/movie "He's Just Not That Into You" said (and as Berger told Miranda) if he doesn't call, as was in Miranda's case, he's just not that into you. Girls are always trying to find reasons why guys haven't called - he's sick, he's busy etc. Stop! If he's into you, you'll know and you won't have to make excuses for them.
2) The importance of girl friends, when Carrie breaks up with Berger or when any of the girls go through anything serious, it's always their girlfriends that are there to pick them up and make them feel better. Too often girls are turning their back on each other and forgetting that we need to stick together. Sure your boyfriend might be great and you see a future together, but if you nourish your friendships they will be there forever for 100%, ready to stand by you even in the hardest times..
3) There will always be someone that doesn't like you, whether it's what you're wearing or the decisions you make in life. There will always be someone that doesn't agree with you and doesn't share your opinions. The point is not to care and to go on with your life. Don't even react to what people are saying, be above it and ignore it.
4) Remember that there is more to a person than what you think, they have gone through things and feel things that you will never know. Keeping that in mind, don't be quick to judge if you don't know the whole story. People have reasons for doing what they're doing and usually it would all make sense if you knew the whole story. More importantly, people need to realize things on their own, nothing you say will change what they're going to do until they come to the conclusion themselves.
5) A million style tips for basically every single girl as each of the main characters in Sex and the City have their own unique style, it's almost impossible not to get some inspiration from at least one of them (if not all!!).
There's a fresh, feminine and more conservative style like Charlotte's, where she's big on dresses and silhouette enhancing clothes.
Carrie, the ultimate city girl, always wearing stilettos and funky, fearless outfits.
Then there's Miranda focuses more on business-like attire, often opting for more comfortable outfits rather than sexy ones. Towards the end of the series though, she is more often seen in dresses and heels!
Lastly there's Samantha, who throughout the series has changed her style many times. Nonetheless it is always sexy, seductive and confident. She can be seen wearing sexy mini dresses or elegant and classy evening dresses.