What is Interaction Design

1) The design of spaces for human communication and interaction
    - Winograd (1997)

2) Designing interactive products to support the way people communicate and           interact in their everyday and working lives 

– Sharp, Rogers and Preece (2011) 

Introduction Of Human Computer interaction

HCI (Human-Computer Interaction) is the study of how people interact with computers and to what extent computers are or are not developed for successful interaction with human beings.

As its name implies, HCI consists of three parts:(i) user(ii) computer itself(iii) ways they work together

Design Principles

Guideline documents are a wonderful starting point to give designers the benefit of experience. Below are some examples:
1) Visibility
2) Feedback
3) Constraints
4) Mapping
5) Consistency
6) Affordance