The 10 Usability principles/heuristics by Dr. Jakob Nielsen:
1. The visibility of system status
2. The match between system and the real world
3. User control and freedom
4. Consistency and standards
5. Error prevention
6. Recognition rather than recall
7. Flexibility and efficiency of use
8. Aesthetic and minimalist design
9. Help users recognise, diagnose and recover from errors
10. Help and documentation
Reference: Molich, R., Nielsen, J. (1990) Ed. Nielsen, J. (1994)Ten Usability Heuristics
[Online] Available: http://www.useit.com/papers/heuristic/heuristic_list.html
These principles were developed by Rolf Molich & Jakob Nielsen originally for “heuristic evaluation in collaboration” in 1990, but have since been refined based on factor analysis of 249 identified usability problems in 1994, resulting in this revised set of heuristics in 1994 by Dr. Jakob Nielsen.