We often get asked "how can I make money from my website?"  Assuming that this is ignoring any product or service you are offering, then the only way to bring money in from your website is to advertise.  There are several ways of achieving this:

1. Link Clicking Generation (i.e. Google Adsense) where by you get paid a small amount for the number of times a visitor clicks on the advert.
2. Subscription (see buysellads.com) where by an advertiser pays you a fee to advertise on your website for a given period. This may be weekly, monthly or yearly. Note that you do not need a third party for this, you could go directly to potential advertisers yourself.
3. Referal Links, for example, 123-reg and EUKHost have systems where if you refer someone to an item/service on their site, and the visitor buys it, you get a percentage of the money for doing so. 

Which will bring the most money? All and none! The amount of money brought in will depend on the number and type of visitors to your site as well as the type and placement of advert.  There is no golden rule to this.  It is easy to go overboard though, so think long and hard.

Which type of advertising should I use? Again that depends, but there is nothing to stop you using all three to maximise potential profit.