I have developed my own theories of social psychology because the stuff out there is structured more for NTs than AS. I think they skip over vast subject areas because those are instinctive for them.
My theories of social cognitive behavior include the fact that all social cognitive behavior breaks down into three phases: impression phase, update/processing phase and expression phase. Let's focus on impression and expression phases for now.
Impression phase is the brain and emotional processing we do as social stimuli come in, and expression phase is the brain and emotional processing we do as we project action and affect.
Impression phase social cognitive behavior corresponds to our sense of identity -- our understanding of the world and our place in it. How we perceive and internalize incoming sensory information.
Expression phase social cognitive behavior corresponds to our personality -- how we project our selves onto the world. It is how we externalize and express emotion and affect.
So according to the system I created (social psychology from an AS perspective), developing affective skills are part of one side of learning social skills, a part that is expressive and action-and-emotion related. Affective skills have to be practiced because there are mental dimensions as well as mood and muscular basis for having a good affect. Affective skills that people can work on include:
How to smile: this is like acting lessons, connecting to your inner child, developing the muscles in your face, practicing until you literally train yourself in how to do some smiles that express different emotions. After you learn some smiles, they will come more and more naturally as you use them and start training yourself to be comfortable projecting emotion to others around you.
How to posture: again, these are like acting lessons, learning how to have certain postures when you have certain moods, like happiness, confidence, anxiety, determination, caution. As you develop a set of postures and body language for different moods that you are in (try real acting methods), your muscles start to do them automatically. Then they will start coming naturally as you start training yourself to be comfortable projecting emotion onto others around you.
Exercise and health: good body tone, energy and action all translate to a more active sensori-motor state and more active muscle response. Exercise is really important to projecting good affect since most of projecting affect involves small muscle groups and requires energy.
Again, developing personality and presence is about the expression phase of your social mind. Developing expression phase skills are all about projecting emotion and attitude accurately and being in shape and practicing real mood-related postures and smiles (i.e. method acting and acting skills) really helps.