First block out land masses, not continents (ie Europe-Asia-Africa is one land mass). Just rough outlines don't worry about details just rough shapes. Earth is only 30% land so unless you want a major change do't go to wild with land masses. The major shapes effect climate on the planet. Any large landmass will be dry in the center with moister coast lines. Continents that run N-S block currents and winds that go around the world, ones that go E-W tend to have the same climate from end to end that helps the spread of civilization. The location of the continents will have a major effect on the ocean curerents which in turn will shape the temperature of the continents.
Ocean Currents Ocean current will try to flow clock wise in the northern hemisphere, from W to E closer to the pole and from E to W at the equator. Souuthern hemisphere current will be the oppisite. A circum-equatorial current will distribute heat better and make the planet warmer and wetter. A Circum polar one will insulate polar continents from warm water and make them colder. Earth has 1 circum polar current which in part makes Antactica so cold, and in recent geologic history South and North America collided at Panama blocking an equatorial current that flowed from the Atlantic into the Pacfic making the temperature of the planet less even.