Aside from the default broad and extended keyword matching options, you can also opt to enforce more limitations in your ads being displayed.

• Phrase match. This limits displaying of your advertisement to exact phrase matches. Simply enclose your key phrase in double-quotes to achieve this effect, such as “this is my key phrase”. The advantage is that your ads will be more targeted, and your conversion rates (meaning the relevance and likelihood of being clicked) would increase. However, the user must enter keywords in the right order, and that means you have to likewise enter each desired possible combination.
• Exact match. This is a more limited version of the phrase match. While phrase match will allow your ads to be displayed as long as the words are included in the query, in order. Exact match means there should be no excess words in the qwery. This is activated by enclosing keywords in square brackets, such as [key phrase here]. Again, the advantage is improved targeting and conversion rates. This is the best means of targeting your ads, so far. However, again, you would have to exclude many other searches, and hence your ad will appear in less queries.
• Negative keyword. When this is activated, your ad will not appear as long as any of the excluded keywords you indicate are appearing in the search query. This is activated by keying in a minus sign before the negative keyword of choice. The advantage is that you can exclude search terms that are of no interest or relevance to your campaign. However, you could be excluding potential customers who could be keying in your undesired keywords in their searches.