The major strategy for the Confederacy in this war was to outlast the Union and, perhaps, to get recognition from one or more important European countries.
In order to win, the CSA did not have to really defeat the North. They simply had to make the North get tired of the war and give up. This would have been much more likely if other important countries had recognized the CSA as an independent nation.
Because of this, the CSA originally set out to fight a relatively defensive war. As time went by, however, they decided to try to invade the North (this is the invasion that led to the battle at Gettysburg) to make the North withdraw its troops from the South.
Overall, then, the South wished to simply hold on long enough to make the North let them have their independence.