My network consisted of just 4 websites, however I spent many hours on each one of them and was quickly worth more then a friends network of over 100 proxies. Each website had a unique design, and each one was optimized for different keywords.
Search Engine Optimizing
Unlike most proxy owners I spent a lot of time optimising my websites for search engines, the best thing you can do is choose a search phrase that you think someone will actually search for, such as “youtube proxy" and base your website around it. You should also have a section on your front page explaining what a proxy website is and how to use it, as most proxy websites are simply a URL form this will help distinguish your proxy website from everyone else’s.
Monetizing your proxy websites
If you plan on making any sort of revenue from your website you need to know where to put your ads to get the most amount of clicks. First put a 468*60 ad directly above and below your proxy bar, try not to make the ads stand out too much. You will also need some keywords for the ads to be targeted at, so a nice description about the website with some high paying keywords. (edit: I wouldn’t recommend using adsense on your proxy website, a lot of people have been loosing there accounts, instead you should try, www.rossjohnson.co.uk/adversal.html)
Advertising your proxy websites
There literally hundreds of proxy topsites out there, so sign up to as many as possible and get your code on your site (preferably at the bottom as sometimes it can slow the loading of your website drastically). You should also submit to directories and proxy.org, if you don’t get accepted then you could always pay for a listing, this will cost just $20 and is definitely worth the money.