After you add mountains, be aware of what that will do to the terrain types near the mountains. Mountains create "Rain Shadows," areas that have very little rainfall. You see, mountains push clouds up into higher altitudes, cooling the water and forcing rain to occur. So on the windward side of the mountains, there will be plenty of rain, which will lead to marshes, forests, jungles, and warmer coastal plains that make good farmland. a good example of this is the Northwestern US- tons of rain falls as the clouds try to pass the Cascades and . then, you see a huge area after these mountains that is desert: the Great Basin, which encompasses much of Utah and Nevada.
Then you need to decide, of course, where the winds are traveling. if you are on a flat world, then you can basically put the winds wherever you want. If you are on a rotating flat planet, the corriolis effect will make the winds follow a certain pattern:
If you are going to follow this model, then you must decide how large your map is (does it lie in one zone? is it big enough to be a part of two zones?) and where it is (which zone is it in?).
Keep in mind that rules were made to be broken. you can ignore some stuff for a better map, and there are definitely other factors that cannot be determined by the winds.