Insights gleaned from these sources are not limited to the passages quoted.
The Magnifying-Glass Icon in Search Design: Pros and Cons (Nielsen Norman Group)
Users recognize and understand the function of the magnifying glass. They see it and associate it with search. If the icon is obvious and has a strong enough affordance that it’s clickable, a separate button labeled “Search” isn’t necessary.
3 Guidelines for Search Engine "No Results" Pages (Nielsen Norman Group)
Ideally, your search engine should understand even poorly worded queries and return a good set of results ...Realistically, we know this process is sometimes going to break down; you can help users recover by following a few simple guidelines on your No Results page:
- Clearly explain that there are no matching results.
- Offer starting points for moving forward.
- Don't mock the user.
Designing Search: Results Pages (UX Mag)
...query reformulation is a critical step in many information journeys. Displaying the current query and allowing it to be edited in place—i.e. within the search box—maintains vital context. In fact, this principle is so fundamental that we often take it for granted...(when current query is not displayed) the user is forced to rely on recall rather than recognition.
8 Design Patterns for Autocomplete Suggestions (Baymard Institute)
It’s a good idea to style the entered and suggested terms differently so the user can easily tell what’s suggested. Most sites do this, which is great. However, most of those sites highlight the terms the user has already entered themselves rather than highlighting the new suggested terms that would be added to the entered query.
Since the user is already well aware of the term(s) they have entered themselves, it makes more sense to highlight the additions in the suggested queries rather than repetitively highlighting the same term in each and every query. This furthermore helps highlight the differences between the autocomplete suggestions, making it easier to scan the differences in the list and thus easier for the user to compare them in an instant.
"...the list of autocomplete suggestions should be kept to a maximum of around 10 items to avoid inducing choice paralysis."
Autocomplete Design Pattern (UI Patterns)
Designing Search: As-You-Type Suggestions (UX Magazine)