I would say recognizing insecurity first starts with body language. You can see someone's confidence, as in the way they walk, hold eye contact, and the way that they sit, either by slouching or not slouching. Another way you can recognize it is by the way someone dresses, if they aren't wearing the clothes as if they are happy that they have them on, then that is a way of seeing insecurity. The way that you talk, if you sound unsure about an answer to someone's question, then that person will perceive you as not knowing or always being insecure. Stuttering, mumbling, looking down, fidgeting may be signs of being nervous but also maybe signs of someone who is insecure and unsure of what to say, think, or do next. There are many ways to overcome insecurity participate in things you like to do, try to make friends, wear clothes that make you feel good, eat foods that give you energy and feel you up, eat chocolate, join a self-esteem class, workout, receive plenty of sleep, talk with family members of friends that you feel with understand your situation. I hope this helps, so sorry this is so long. Best of wishes.