My first map

[Marken4]

Looks nice for a first map, I'm not so sure about the ocean though. I would have blurred it or something...

[trexmaster]

You have some splitting rivers, one in the north (with one branch flowing into the lake), another in the northeast, and yet another on one of the southeastern islands. As has probably been pointed out many times on this forum, rivers do not split like that, except maybe at deltas.

[loongtim]

Looks nice for a first map, I'm not so sure about the ocean though. I would have blurred it or something...

CC3 has a feature called "Sheets" that allow you to apply effects to your maps, similar to PhotoShop filters. So, as Marken4 suggested, you could use the sheet effects to blur the ocean, coastlines and land background transitions, etc. If you bought the downloadable version of CC3, you should be able to login to your account and find a tutorial guide that will explain sheets and show you how to some basic effects like blurring the ocean.