One of the key tools that you will find most useful across all databases and also search engines like Google or Bing is the phrase search.
The benefit of this type of search is that you can use it to get around the database's standard search approach of looking for all of your words singly and giving you results for each one. Instead, you can force it to search for a phrase - in other words, show you results where all words in a phrase appear exactly as you've typed them in.
The symbol for a phrase search is the double quotes key "like this" which is SHIFT+2 on a Windows keyboard and the double quotes symbol or the quote key for a Mac or Bluetooth keyboard.
For example, if we search for health promotion - the database will look for health anywhere, promotion anywhere, and health promotion together so you'll get a lot of irrelevant results, especially if you're using a supermassive resource like Library Search.
But if we search for "health promotion" we'll get fewer results and they will be more relevant because we've told the database to show us articles or books where health is immediately followed by the word promotion with no other words or punctuation separating them.
If you only ever use one search tool then the phrase search is the most important that I would recommend.
Have a look at the example searches with results below:
health promotion (without speech marks - search on Library search)
"Health promotion" (with speech marks - search done in Library Search)
And then, if you add in an extra word or two, or a phrase to make your search a little more specific, you can narrow your results further without losing relevancy.
Truncation is another tool that can be useful even in a basic search. Truncate means 'to cut off' and in terms of searching it means we remove the end of a particular word, leaving behind the stem which is shared by multiple terms so that we can look for them all without having to type every word in.
So you could use it to look for words that have a singular ending of 'y' and a plural ending of 'ies' e.g. therapy / therapies or you could look for words that start with the same set of letters no matter the range of endings e.g. ocean / oceans / oceanography / oceanography / oceanographer
The symbol for truncation is an asterisk (SHIFT+8 on your keyboard) and always goes at the end of a sequence of letters.
So for the therapy example, you would type into the database or search engine search box: therap*
For the oceanography example it would be ocean*
You can also use the truncation symbol at the same time as using phrase searching, so you could have "occupational therap*" which would find 'occupational therapy' / 'occupational therapies' / 'occupational therapist' / 'occupational therapists'