Knowing others helps in deciding what kind of relation you want to pursue with them.
An adequate knowledge of a person’s qualities, temper, skills, limitations etc is essential to form a lasting and meaningful relationship. Without proper understanding, there can be conflicts, misunderstandings or fights, which leads to sadness and disappointment.
The best way to know others is by interacting and communicating with them. Start making light conversation in the beginning. Do not ask very personal or direct questions, as the person may resent your forthright questioning or interest in them. Start knowing a person by asking about their hobbies, favourite stars, movies, colours, music etc. Disclose about yourself too.
Slowly you can steer the conversation to their family, occupation, siblings, important occasions in the family and so on. Maintain a certain degree of consistency and sincerity in your interest to know them better. At the same time, do not pry or intrude too much on their privacy.
You can also know people by reading more about the star sign they belong to. People belonging to the same zodiac display more or less similar characteristics. You can browse through various sites on the internet, and get to understand the deeper personality traits of the person.
Observe their behaviour when they are with others too. You may pick up clues like their comfort level with gender, ease with co-workers, behaviour with people in positions of authority, their level of comfort in speaking with you vis-à-vis others. It can give you an idea if the person is friendly, reserved, open, honest, confident or is moody, bad tempered, dishonest, showy and so on.
Body language and handwriting can also reveal their personalities to you. You can refer to the internet and learn what a particular body posture indicates (especially hand movements, facial expressions). By doing a course on handwriting analysis or by using self help books you can understand the personality of a person with a particular kind of writing style.