|Should I use all 3 options?|
Currently, I have my keywords with [ ] around them. Should I also add in the same keywords but with " " around them? And also with nothing around them?
What happens with all 3 options?
Another seperate question: I have an Adgroup with a large not very well focused list of keywords. They all have " " around them. What will happen if I put [ ] around the same keywords but also have the " " ones left in there too? Will this mean I get cheaper clicks on the exact match and the same price on the other ones or what?
As you know, there are some factors that determine when an ad should appear on a SERP: Max. bid, daily budget and concordance options. Your question is related with the concordance options and work as follows:
1) When you put a phrase into [ ] the ad only appears when there is an EXACT match with the search term (nothing before/nothing after your phrase in the search term)
2) When you put a phrase into "" the ad appears when there is a PHRASE match with the search term (anything or nothing before the phrase / anything or nothing after your phrase in the search term)
3) When you put a phase without [ ] neither "" the ad appears when there is a BROAD match with the search term (every word or combination of words of your phrase in the search term)
So, if you put a phrase into "" you cover the PHRASE MATCH and the EXACT MATCH and if you omit [ ] and "" you cover the EXACT, PHRASE and BROAD MATCH.
In general, the broad match should give you more impressions than the phrase match and the phrase match more impressions than the exact match. The CPC also varies regarding to the concordance options and the demand of the phrase.
Hope that this helps,
Well, I was thinking that if I had the term My Pet Dog in both "" and  then the  should have a better CTR if the advert is nicely targetted with My Pet Dog in the title.
Someone searching on My Pet Dog would see the exact name in the title and hence be more likely to click than if they typed in My Pet Dog New York.
Consequently, I would expect a better CTR and therefore lower cost per visitor for a exact match than a phrase match.
Does this tend to be true?
Seeing one's search phrase in the ad itself is considered desirable in general. I'm pretty sure that has been scientifically tested and proven. Therefore that's a wise goal on your part to attempt to ensure it.
However, which words are bolded in the ad is determined by what they type for their query, not what your keyword phrase happens to be. So it's just as likely they'll see 'my pet dog' because that was part of a broad match as it is if it were part of an exact match.
So if they typed 'bones for my loving pet dog' and you had the good fortune to match that with a broad match of 'bones for a pet dog', they'd still see my pet dog bolded assuming that phrase appeared in your ad.
The consensus here is that using all 3 match types where appropriate is desirable for various reasons. To better exploit the concept of echoing one's search back at them in your ad, you could also try using dynamic keywords. The concept is best described in this thread, message #3:
As far as I know, if you set the phrase "red widgets" as phrase match it should appear in response to the search terms "red widgets" and "cheaper red widgets", but in a lower position in the second case (depending on the match type and the max. CPC chosen by the upper positions in relation with your max. CPC).
If you choose the phrase match you'll cover all search terms containing the phrase "red widgets" as is, including this one, so the exact match is covered, and you can set a higher max. CPC to gain a higher position for the broader coincidences, heaving in mind that the Adwords engine should set the correct CPC on each situation.
This requires also corrections in the negative coincidences to avoid undesirable search terms (Ex.: "red widgets in Toronto" if your business is located in Roma).