Infinite Scrolling: When to Use It, When to Avoid It
The Magnifying-Glass Icon in Search Design: Pros and Cons
However, for accessibility reasons, remember to include the word “search” or its translation as an ALT text for any graphics-only button.
10 Usability Heuristics for User Interface Design
Jakob Nielsen's 10 general principles for interaction design. They are called "heuristics" because they are broad rules of thumb and not specific usability guidelines.
Overlay Overload: Competing Popups Are an Increasing Menace
Today’s users are overwhelmed by a plethora of site and browser-initiated popups with content unrelated to their current task.