Server runs out of RAM - How to make more efficient?

My website seems to go down for up to an hour almost every day. I don't know much about servers so would appreciate advice on what to do next.

The website (3dsbuzz.com) has a Wordpress section, Wiki, Gallery and a VBulletin forum each with their own custom code and plug-ins. So there are lots of potential places which could be inefficiently coded. It runs from a cloud server with 2GB of RAM. The MySQL database is 370MB. We get around 30,000 page views per day.

What wo开发者_如何学Culd be the best way to reduce the amount of down time? Should I upgrade my server (I can't really afford to) or is 2GB reasonable? I have plenty of errors in my error log, but they don't always occur around the same times as the server going down, so I'm not sure how relevant it is.

A solution is to remove each conponent one by one until the server no longer crashes.

Then, you know where to look for and can investigate further.