For someone who went to a school whose purpose was basically to train kids to become missionaries, I actually don't know if I have any useful advice on this front. Well, I suppose I can start with the more cynical, pragmatic advice: do your research before packing up and moving your entire life overseas. My parents knew this one family who had a fellow from Nigeria visit their church asking for people who were willing to serve overseas, and so they decided to sign on and become missionaries. Unfortunately, when they finally arrived there they realized that the man had completely misrepresented the situation to them and they got swindled (kind of like a Nigerian email scam without the email, I guess). Be extra careful and pray extensively before taking anything on in the mission field. If something doesn't seem right, listen to the Holy Spirit and to your gut.
Also, and while this may sound somewhat in conflict with my first advice because it's a bit of a wild card, fancy Bible college degrees and official denominational backing do not always a good missionary make. I've always thought that it's a stupid idea to deem spiritual leaders worthy of their calling (pastors, missionaries, etc.) based on the amount of college education they receive. Literally any bum who fancies themselves a spiritual leader can sign up for four years of college and get themselves a degree for the denomination of their choice, and let me tell you, there
are a lot of bums who do just that. That's not to disparage all "official" missionary organizations, but just remember that there is more than one way to becoming a missionary. Something great my Religious Studies teacher had us do for our last semester, and it's something I recommend you do too, is that he had us read a bunch of biographies and autobiographies about various missionaries and martyrs, both past and present--I loved
God's Smuggler by Brother Andrew, by the way. Be careful as you read different testimonies, because like I said, any quack can become a spiritual leader (and then write a book about their freaky theology), but start investigating--what's the difference between a missionary who feeds a village by getting their denomination to foot the bill, and a missionary who feeds a village by praying for food every single day and receiving it by faith? (An example of the latter, I do believe, would be Heidi Baker. She also heals deaf/blind/dead people.) Also, some people start their own missionary organisations, like
http://www.aslanintl.org/, which publishes Bibles in Turkey and reaches out to Turkey's vast Muslim population.
Oh! I just remembered something else: be careful of mission/aid organizations that foster a dependency on foreign aid and assistance to maintain people's well-being. While it's important to help people with aid when they're in immediate peril, long-term it's harmful to ship free hand-outs to these people because they soon become reliant on gifts on donations rather than their own means, and that can serve to further disempower them and cripple their local/national economy. That's why I really enjoyed my school's short-term mission with
http://www.impactministries.ca/ in Guatemala; they've set up private schools around the Tactic area (families pay to attend, though there is also a sponsorship program available) that not only offer children a quality education but also regular meals and access to healthcare for the students and their families. The majority of the staff is Guatemalan, many of them either former students or parents of students, and the goal of the schools is to educate and empower Guatemalan children to impact their country and the entire world for Christ--a lot of former students have gone on to receive university educations, and the ministry's hope is to also train up Guatemalans to become missionaries in places where white, high-maintenance North Americans stick out like a sore thumb, such as in the Middle East. While the the ministry was founded and is run administratively by Canadians, ultimately the organization is about empowering Guatemalans (through the power and love of Christ) to help themselves, and I think that's a lot more powerful than being an endless source of free handouts.
...Okay, so maybe I did have some advice.
Hope this helps!
