Finding GameSend and game crypt functions using OllyDBG

Generally most games will encrypt the data right before they send it.
With that knowledge we just have to find where the game sends it. Then we can look above it or before it to see where the game encrypt function is.

Packet Analysis

You will want a way to sniff packets perhaps WPE Pro or wireshark, could use ollyDBG or code your own sniffer/logger.

And also a way to check out whats in the packets hex and do simple operations like XOR. I suggest 010 Hex Editor its amazing.

Packets are the things that hold data to be communicated between the server and client, or client too client(s).