Mormon Life says: Some good advice here.
Returned Mormon missionaries can generally be divided into two camps: those who hated the Missionary Training Center and those who loved it.
Last week, my sister entered the MTC, and ever since I've been wondering what advice I could give her that would make it an enjoyable experience.
Here's what I came up with:
Speak your mission language
Look, I know you don't like speaking your mission language. Nobody does at first. It's not fun trying to make jokes or tell stories or get to know your companion in a language you can barely speak. But trust me; it's worth it.
Consistently speaking your mission language in the MTC will make the difference between spending your first transfer participating in the conversion process vs. falling asleep in the lessons. But I think it goes beyond that.