Talk about yourself and your business
Make the text different from what’s on your landing page
Use a passive verb in the headline
Write several ads and see which one performs the best
Use all capital letters in the headline
Make sure the headline wraps to two lines
Capitalize the first letter of each word in the headline
End the headline with an exclamation point
This practice is called Ad rotation. This is an experiment type activity to find best performing ad among several ads. If you have multiple ads within an ad group, your ads will rotate because no more than one ad from your account can show at a time. Use the ad rotation setting to specify how often you’d like the ads in your ad group to be served relative to one another.
Read more here: https://support.google.com/adwords/answer/112876
Ad rotation is the way we deliver your ads on both the Search Network and the Display Network. If you have multiple ads within an ad group, your ads will rotate because no more than one ad from your account can show at a time. Use the ad rotation setting to specify how often you’d like the ads in your ad group to be served relative to one another.
The optimize for clicks setting gives preference to ads that are expected to attract more clicks than other ads in the ad group, based on your past clickthrough rates (CTRs). With this setting, your ad group will likely receive more impressions and clicks overall, since higher-quality ads attain better positions and attract more user attention.
For video campaigns, ads are optimized for views (instead of clicks) using the same methodology. All video campaigns are automatically optimized for views.
How it works: As data is accumulated, ad serving will become weighted more heavily in favor of the ads that appear statistically likely to perform better. Ads expected to attract more clicks are delivered more often into the ad auction than other ads in the ad group. These ads show more often, resulting in higher ad-served percentages. However, it’s possible for ad serving to remain relatively even within this setting, if ads in an ad group have similar performance or if the ad group does not receive a substantial amount of impressions and clicks for some period of time.
Keep in mind: The ad with the highest CTR may not always be the one expected to get the most clicks. That’s because the number of clicks an ad is expected to get is also affected by how often an ad is eligible to enter an auction. Expected CTR is only one factor of Ad Rank, which also considers landing page experience and ad relevance (among other factors) when determining your ad’s position and whether it will show at all. So a more relevant ad with a better landing page experience but a lower expected CTR could be eligible to show on search results more often. That can, in turn, lead to a higher overall number of expected clicks.