Spotlight is a great search tool that ships as a part of iOS, but the results it puts forth aren't necessarily what you'd expect, so here are some tips on getting what you need out of Spotlight.
Launch the Settings app, tap General > Spotlight Search. You'll be presented with a list of items that Spotlight searches for: Applications, Contacts, Music, Podcasts, Videos, Audiobooks, Notes, Mail, and Events.
By default, each of these items has a check mark placed next to it. If it is checked, then items of that type matching your search criteria appear in the results. Tap the items individually to toggle the check mark on and off; those that are marked off those will not appear in the search results.
Finally, you can change the order in which these items appear in the results. Tap and drag them up and down in the list to change their order by grabbing the icon that looks like three horizontal gray lines on the right hand side of the screen. Once you have the item moved to where you want, let it go.
Compatibility: iPhone, iPad, and iPod touch.
