You just have to be confident in yourself. And despite the stutter, people will see you as a confident person. It took a long time for me to get there, and to be honest I'm still working on it. Most people are at first a little confused the first time they see me have a block, but it's just something you brush off. The same concepts for human interactions apply. Have empathy for the other person and take a legitimate interest in their life, and they will do the same for you.