Google announced the new feature of Gmail “Search Autocomplete”. Just go to GMail setting> Labs> Search Autocomplete. Enable the lab app. After enabling the feature you will get suggestion in the search box of GMail while typing exactly in the same manner as you search in Google search.
Now you will get suggestion if you type any letter on a search box.
If you are not satisfied with the search then Google has a surprise in your pocket, advanced search operators, which gives you a more advanced way to find any message you have in mind. Your search becomes specific ,if you want to search for a chat session or for a photo, just type “photos” or “pictures,” ,In a Similarl way, you can type in the word “attachment” and Search Autocomplete will list the most common attachment types for you.