One may think that all missionaries are evangelists. However, once an evangelist has successfully done his or her job, and faith has taken hold in someone's heart, what then? How will that new believer be nurtured along? Surely, just as necessary are missionaries who can disciple, others who can teach, and others who have a pastoral touch to strengthen and encourage. (Super-missionaries, who can do it all, are very rare.) Sometimes the most powerful and effective witness is done by people who say little but serve with love and compassion, who are there to give practical help when others need it most. A gift for hospitality, or for making friends - there are times when such things are exactly what God wants to use in someone else's life. And the greatest contributions are sometimes made by those who take the grungy, practical work upon themselves so as to free up other missionaries for ministry.
The point is that missions is a large team effort, and there is a need somewhere for just about any kind of giftedness. Often we don't know beforehand, or are outright mistaken, about how God will use us. So, if you look in the mirror and think, "How could I possibly be of use to God overseas?", don't give up hope. There is an even more important question here.
Far more important than the particular gifting is the heart that goes with it. When God's love changes our hearts, and we begin to look around us through His eyes, there naturally arises within us a heart to bless and serve others. We see needs, and what we can do to meet them, and we step forward and are used by God to bring blessing. The real question to be asking is "How am I being used by God to bless others?" That is often the best indication of both the type of gifting one has, and the state of one's heart in service.
A servant's heart doesn't magically arise when one is plunked down overseas. The degree to which you are pouring yourself out for others now is probably the best indication of how you would be elsewhere. And, in considering fitness for missionary life, it probably doesn't matter so much whether one is doing this versus that, so much as whether one is doing it serving the Lord and others.