Yes, it's a bit like a Total Quality Solution approach. Small steps add up to a large improvement.
I've recently been optimising a few of my smaller sites. I have a site in a high paying niche, but I've had poor traffic for it, so I've been really concentrating on keyword density, a more meaningful domain name (featuring keywords) and trying to get that traffic up. I have put it onto a sub-domain of one that is already heavily indexed in Google. This small site I have moved boasts a CTR of between 10 and 15%, but has only been getting small numbers of impressions for it's ads (a couple of views per day). It's generated 10 clicks from 71 impressions this month for $7.68 total. I know that if I can get the traffic up to a reasonable level, this site alone will add another $50-$100 per month, maybe more. I'll let things settle down and i'll report back to tell you all how it's doing.
PS. That previous record of $145 has now gone. I'm looking for a new high !