Look to the signs on the 5th house, the 7th house, and the 11th house, in that order, to figure out how you make friends. Then, look at the rulers of those houses and see what is going on with them. Usually, by the time one is an adult, they are already aware of how easily they make friends, what kinds of friends they attract and/or prefer, and under what conditions they make friends. However, some people just aren’t geared toward having a busy social life and may benefit from a deeper understanding (especially if the rulers of any of those houses is intercepted or in the 12th house).
Like many things astrological, where a person is insecure is complex. One of the first places to look at is the sun. If you consider Dane Rhudyar’s mystical work, and that the sun is bright but also casts a shadow on the other side, where you are insecure is a combination of the sign and house of the sun and also the sign and house opposite the sun.
So, for example, if you have the sun in the 2nd house, you may have an ego need to be secure, have comfort, money in the bank, and possessions. The shadow of that is insecurity about sharing (8th house) with others, especially joint assets, and of risking investment of some of what you have (2nd house) to have even more and creating a legacy (8th house).
If you have the sun in the 10th house, you may have an ego need for high status and social power and influence, with the shadow in the 4th house, meaning that you ignore your origins or need for family, or, in more extreme cases, are trying to escape the reputation and fate of the family of origin and climb the social ladder. However, it can be lonely at the top, especially with no one to come home to and no one to root you in reality or love you simply for being (4th house).
I have the sun in the 9th house, the house of travel and philosophy. I have a need to learn, to grow spiritually and intellectually, and to explore. The shadow is in the 3rd house, the house of communication and basic intelligence and basic learning. I will leave you to that one.
But it can get even more interesting! Say you have the sun in a house where it is not comfortable, like the 11th house. This is the house of friends, social connections, aspirations and collective dreams. This is a house of we, not me. The sun isn’t happy here (not devastated). The shadow is in the 5th house of pleasure, romance, children, and fun. One way this could manifest is as the tireless advocate who takes no joy in life, or someone who relates to people intellectually or in groups, but not personally, or for fun. The 12th house is even better. Here, the sun is hiding from the native, but seen by the world. While the desire may be to dissolve, to fade away, or to be at one with the universe (which is sort of the same thing, really), the shadow is in the house of routine, the mundane, and servitude (6th house). This is the starving, or even accomplished artist with the cockroaches in the kitchen and the bills gone unpaid.
Conversely, the shadow may be the place one retreats to when the ego is bruised. 9th house sun culls from different sources why it is not wrong. 10th house sun compares itself to it’s roots and sees how it has risen from the gutter. 12th house sun becomes inordinately obsessed with details (yes) or minor things to the point of making themselves sick (6th house). 6th house sun, on the other hand, can go deep into soul-destroying criticism that can spark an existential crisis over a passing thing. The 11th house sun gets way too into the schmoozing and the celebrity that his or her public work brings, and it goes to his or her head (5th house), especially if they are the lucky 11th house sun people who find themselves with a fan club (5th house). 8th house sun will deal with insecurities about sex and sexual partnership by masturbating (2nd house).
The last one wasn’t entirely a joke (those folks know exactly what I mean).