Welcome to the guild!
It seems to me that you've got a good start on your map. Where you go from here depends on how detailed you want to get. Some people start with tectonic plates, elevation and climate maps. IMO, that's a lot for someone just starting out; I know just reading about them made my head spin!
So this is my suggestion:
1. Start with style. Are you wanting realism or something more artistic? Somewhere in between?
2. Are there any major features (i.e., cities, mountains, forests, deserts, etc.) that you know where you want them placed? These can give you a starting point to work off of. Example: for the map I'm working on now, I knew I wanted there to be a desert separating the northern and southern parts of the western continent, and that I wanted the city where most of the action is taking place to be near a river on the eastern continent .
3. If you get stuck on a particular part, try looking at maps of Earth. I thought my map didn't have enough lakes and rivers, but after cruising Google Earth I realized that most rivers and lakes wouldn't be visible at the scale I'm working with.
Hope that helps!