Touch Target Sizes People interact with touch-based user interfaces with their fingers. So user interface controls have to be big enough to capture fingertip actions without frustrating users with erroneous actions and tiny targets. Ok, so how big? — by Luke Wroblewski
How to Conduct a Heuristic Evaluation by Jakob Nielsen Heuristic evaluation involves having a small set of evaluators examine the interface and judge its compliance with recognized usability principles (the “heuristics”). See also Konigi’s Heuristic Evaluation Reference.