Search strategies should relate to a website’s mission and message. They also need to respond to the anticipated user skills and preferences – optimal search strategies on a website for scientist or engineers would be quite different from those for the general public.
Search is really just part of navigation. In many cases information found by running a search routine can also be found by just browsing through the pages. Which serves the visitor best? … is that also what serves the mission best?
Search needs words (also phrases) for searching. When visitors compose their own phrases, will those phrase be effective in searching the website? If not, then search terms should be offered as items in drop-down lists or some similar selection interface.
Next there is the question of what will be searched. A Google-like search can theoretically see every word in the public space of the website. Will this work OK? … will many irrelevant items be returned? … or should that type of “free word” search be used, but restricted to parts of the space with relevant content?
Another approach uses either “free word” input or “selected word” input to search only prepared fields in the database. This allows the web administrators to help or control the search results, but requires maintaining those fields of search phrases.
Many choices and variations are possible. Least expensive is installing one of the free search routines, one that can be limited to just the one website, as Google can. It has quick setup, little maintenance, is familiar to nearly everyone, but in a small website it can be quite imprecise and may often return empty lists.
I recommend a careful discussion with your website’s Information Designer.