I always recommend that people read the book How to Win Friends and Influence People. This book has taught me a lot. If you don’t have time to read it or at least read the lesson summaries on the Wikipedia page for the book.
Someone brought up the issue that if you practice the principles discussed in the book in real life it may make you seem fake or forced. This is absolutely true! (See video above). The fact is, it’s really, really hard to pretend to like someone. So how do we solve this?
The answer is to create habits out of the good practices taught. A habit is something you do without a conscious awareness of doing it. If you create a habit out of never criticizing people, then the next time they say something really, really stupid, you’ll look less like you’re holding in a fart resisting correcting them and more like a naturally nice person.
I recommend you read The 7 Habits of Highly Effective People is an excellent read after you read How to Win Friends. It talks a lot about the creation of habits and how we can use habits to improve ourselves.