The NYT Magazine has a piece discussing Greece prospects for increasing its exports. While it will certainly have to increase its exports to have a sustainable trade deficit, it is worth noting that a lack of exports was not Greece main problem.
From the inception of the euro in 1998 until the crisis hit in 2008, there was only one year in which Greece's exports fell (2002). In three years, exports grew at a double digit rate.
Greece has a serious trade deficit because its imports grew even more rapidly. The return to sustainable deficits will almost certainly mean that Greeks will again have to produce domestically some of the items that now import and do without others (e.g. fewer Mercedes).
Fifteen years ago the country had sustainable trade deficits. Its exports are considerably higher today than they were then. This should mean that there is considerable room for adjustment on the import side.