If you want to start as early as you can and work forward, begin here. Use tectonic plates and their movements to determine continents, coastlines, island chains, mountains and ravines.
Use Geoff’s Cookbook to work out the placement of climates/biomes using wind patterns, ocean currents and lattitude to create a realistic world.
A tutorial on drawing resource maps and using it to develop your world with trade routes and trade goods. Includes a list of trade goods.
A guide on drawing culture maps and grouping them based on terrain, history and other factors and using it to generate plot points for your world.