How much money can we make on CIAO?

Yes someone does have a system, Ciao does, in their site guidelines. If you read that and stick to the rules, you can make decent money there not by listening to strangers on a website many of who will encourage you to add them and rate their reviews in exchange for rating theirs - behaviour which will get you banned from the site as it's against the rules. Simple formula - write decent quality reviews in your own words without copying from other people's work, read and rate other members on the site fairly and they will automatically come and read and rate your reviews, which will make you money. Aside from the simple formula you really need to READ the site rules to make sure you don't inadvertently break the rules as once you're banned from the site, there's no 2nd chances!