I changed the way keywords were entered last week and the CTR went up to over 6% on each day since. Number of clicks also improved by over 30%. Daily cost reduced by about 20%
Google give an option for having exact phrase by putting "inverted commas" before & after each key word / phrase.
Example "Yankee Candles" advert will only appear when someone keys in Yankee Candles whereas Yankee Candles without inverted commas will appear when somone keys in "Yankee" (they could be looking for info on american football) or "Candles" and then everyone looking for any type of candle will see the advert rather then the more targeted customer looking for Yankee Candles.
Same for most products such as "Poker Chips" "Board Games" etc etc.
If your ad group contained the keyword tennis shoes, your ad would be eligible to appear when a user's search query contained tennis and shoes, in any order, and possibly along with other terms