Memory leak and troubleshooting

To date, I've had about 175 of these Error R14 (Memory quota exceeded)

per hour.

Now I have restarted my dinosaurs and it seems it doesn't, but I don't think it will go away on its own.

I've heard good stuff about Oink and the Mini Profiler

How do I get started? How do I find a piece of code that is a memory leak? Are there general guidelines?