Just draw out a continent or two on paper and once you're happy, translate them into a digital format, adjusting as necessary. It's probably helpful to narrow down the task at hand: concentrate on one continent at a time, and don't try to get overly detailed to begin with, that really isn't necessary for a first sketch. You're probably overly exaggerating that some shape "feels wrong" if that's how you feel, or maybe you didn't sketch things enough on paper beforehand to have a clear vision about how you want the shape to turn out. Things rarely work out for me either if I just sit down to "draw something" before first creating a paper draft about what the shape/layout should look like.
Basically, I think you need to be more patient with yourself and get rid of the perception that anything you draw is "automatically wrong", and probably draw a lot more quick sketches before settling on the final shape. Remember that your first creations don't have to look perfect: drawing maps is something that you get gradually better at and develop an "eye for shapes", but you need to keep doing it in order to develop those skills
![Wink](images/cartographer/smilies/wink.gif)
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Btw, if you haven't done so yet, I'd recommend checking out Tiluchi's
Pangarap (and his earlier
Ayesha): that should give some ideas about how to get started with a project like this.