Use the following tips to optimize your searches:
Use "&" to find images that contain both words:
water & fall
Use "|" to find images that contain either word:
water | fall
Use "-" to find images that contain "water" but not "fall"
water -fall
Use "(" and ")" to group parts of the search
(water | green) fall
Use quotes to match a phrase
"the water fall"
All of these may be combined
"Along the Oregon coast" & (water | green) fall