I assume from the 2:1 aspect ratio that this is meant to be in Plate Carree projection. That should produce significant distortion of the polar regions which your map doesn't show. The two small continents in the north should be stretched out east to west. Since they aren't, it means the "real" shape on the globe is pinched in toward the poles.

Here's what it looks like in a polar stereographic projection which shows the pinching.
Click image for larger version.  Name: Untitled map.png  Views: 63  Size: 57.5 KB  ID: 44302

Plate Carree is simple and convenient for data that is going to be reprojected, but it's not a very good choice for a finished map.

Your coastlines are also a bit consistent. If you look at Earth, you'll see that the degree of "crinkleyness" varies. There are smooth areas like the Atlantic coasts of Africa and South America, and there are massively complex areas, like Southeast Asia or Scandinavia.

You do have a bit of a divergent boundary thing going with the two larger continents that resembles the Atlantic basin. That's good. The west coast of the big one looks like it fits with the east coast of the smaller one. I'd suggest you play that up by not running any tall, young mountains along those coastlines. Old rounded ones like the Appalachians (Which run along the east coast of the United states) would fit though.

You're also rather lacking in islands. There are a exceptions, but in general, most major islands are found along convergent boundaries, along with young mountains. Such islands essentially are just mountains or mountain ranges that are partly underwater (Japan, the Philippines, Indonesia, Vancouver Island), while the other kind like are essentially partly flooded plateaus (Great Britain, Greenland, the Canadian Arctic), or mountains in odd places (Hawaii, Iceland).