Hello Khalis.
The shape looks already interesting and nice, full of opportunities ... I can already see sprawling ancient civilizations and realms around...
Did you completely generate it or you painted it?
Anyway for sugestions it really depends what you want to achieve, if you want to go for a full geological plausibility , then you have a lot of work to implement , like designing plaques, continental drift, age of planet, gravity and all other stuff that you can find in the Pixie WIP-tutorial
But in all Honestly its a lot of work that you can skip simply by placing plausible mountain ranges, and biomes... After all what you want is a belieaveable world to play and not spend the next months on it , if I am not wrong of course...
The shapes are to me already very good and belieaveable, the mountain ranges already can design big collisions of plaques especially in the right continent.
The left one seems instead having received a pretty big erosion or perhaps is younger ... may be is made of plaquest that are separating from each other ...
Consider that there can be also a lot of other reasons why a continent might feature less mountain ranges ...
That said I wouln't stress too much on it , because the placement of mountains seems already plausible to me .
Now on the map itself I would make a more rugged coastline on north , with fjords , smoothen the large coastlines of continents that are separating from each other, or accordingly to what might seem to you the actual movement of plaques...
Imagine the continents float over a sort of dense liquid and that liquid shifts around the continents that are not solid but malleable and deformable , so they can change their shape according to twists , stretchs, compressions and movements.
apart that its all fine and apart some minor fixing here and there like adding or removing some lands you can pass to the excellent tutorial of Israh
Wilbur tutorial
For biomes you can follow this tutorial
Good luck with your project .