Gain Your Kid's Trust And Confidence
Your child will now only confide in you once he is confident that you will understand and support him in everything. So your first job is to build this trust. Start sharing your secrets with the child and make him feel that you trust him. This would encourage him to trust you back and tell you his secrets too.
Never tell stories or laugh about your kid’s failures or weak points in public. For you it may be a funny story, but for him, it will appear as a betrayal of himself, and he will be scared to open up to you about anything negative ever again. which can be quite troublesome for both of you in the long run.
Another way of winning your kid’s trust is through your reaction when he does something wrong. If you scream and freak out, he will start hiding things from you in fear of your reaction. So restrain your temper and treat any misdemeanour firmly but calmly.