Take one of my pages, http://www.wildbackpacker.com/destin...skingulch.html, for example. On the right side of the page, I have Google Adsense Ads. This is a long page, so I have room for several skyscraper ads. However, Adsense has the rule that you have only have 3 ads per page, correct? Well what do I do with my extra space? I want to make as much money as possible, without annoying the visitors. Should I space them out more? Just deal with 3 advertisements? Put other companies ads there? What should I do to make the most money?

you have only have 3 ads per page, correct

Not quite.

https://www.google.com/adsense/suppo...py?answer=9735

Didn't know I could still have add units as well. I'll have to add some. Thanks! Also, the heat map is quite helpful. https://www.google.com/adsense/suppo...y?answer=17954

Don't put extra ads units, generally adding more ads don't mean you will earn more, earning depends on clicks.

You can sell your extra space for pay per month 125x125 ad blocks and like that, or you can advertise or highlight your own site, product or article there.

Another option is to use other advertisers to fill the gaps on your page like Infolinks and Adbrite.

Google use to be funny about using ads from other companies on pages displaying their ads but they've relxed the rules on this now. So if you wan to maximise the use of the space on your website consider other advertising services.

Yeah Paladin, Infolinks is the best option in this regard which can be used along with Google adsense.

Well I've looked into in-text advertising, but I don't like it at all. I've never used Infolinks, but most of the time they are all irrelevant (such as with the case of adbrite). So I'm not sure if I want to go in that direction. I added a Adsense Links unit at the bottom of each of my pages and I've almost tripled my income, so that helped a bit I don't want my pages to be filled with ads, so I think I've reached my limit. I just need to work on getting more traffic (which is for some reason going down...)

not actually
just one is enough,
so that visitor would click the ad which has highter price.
and eCPM would be good

I no longer clutter the page with adsense ads, just use 1 and in a very few cases 2. The problem with them is....they all ook the same !!!!. The visitors gets tired of them and they just ignore them no matter how good the ad there could be. Build good traffic and just then you will be able to get other ad companies. The 125x125 blocks are another good option to work with.

If you have a good site you can get private advertisers and charge them like a bull, if you got a crap site stick more adsense on it.