Summarizing some thoughts on interaction design after getting into Designing Web Interfaces by Theresa Neil & Bill Scott…
Make it direct. How immediate is the action? Allow users to interact quickly and efficiently with your design by not obfuscating functionality.
Keep it lightweight. Allow of micro-interactions that don’t take your user out of the flow. Little Big Details.
Stay on the page. Reduce the need for adding extra content by using elements like overlays, i.e., a dropdown menu or pop up.
Provide invitations. Give your user the tools to understand where they are headed. Use explicit calls to action, and don’t leave your user wondering where to go next.
Use Transitions. Illustrate the action just taken. Error message with animation instead of text. iPhone camera button.
React Immediately. Respond directly to input, changing input, indicate progress, prevent errors before they happen.