1) Remove generic single word keywords from the campaign
This will typically improve CTR and conversions. The more specific keywords usually perform much better and the general keywords usually perform worse.
2) set content match on along with search match
This will almost always lower CTR and conversions. Content Network (AdSense) typically does not perform anywhere near as well as Google and the Search Network.
3) make all keywords as phrase match
This will typically improve CTR and conversions. As you move from broad match to phrase match to exact match, you get more specific. Be careful, though, as some broad matches are fine. You don't want to throw out the baby with the bath water.
I would recommend reviewing your keywords individually to determine which ones should be deleted, which ones you should just lower the bid on, and which ones should switch to phrase or exact match. If you aren't getting an acceptable CTR and conversion as it is, I wouldn't recommend introducing content match.