Coastline may be too uniformly wiggly - like Gidde says, there's ways to generate varying degrees of jaggy, plus you can use a bit of logic. Rough landforms can carry on out to sea; there the coast might be highly indented and the bumps that happen to start below sea level may stick up as islands. Places where your landforms are low-relief, like marsh, plain, savannah -- those might have smoother sweeps of coast.

As for location of the various biomes - nothing too unlikely about your swamp then forest then savannah progression. The neighboring peninsulas, one arid and one heavily forested need some rationale. A way could be for you to run the eastern Kobolds' mountains all the way up the coast to the northern cape above your desert. If you then figure your year-round prevailing winds there are out of the west, you could get what's termed a rain shadow - drier climate downwind. Assume the forested peninsula has a bit more northerly winds, and its mountains would actually collect extra rain - humid air pushed upslope tends to lose its water as rain.

Guess that the western coast has a warm current running up it, and the whole western half of the continent could be a bit warmer than otherwise (though the effect would be most pronounced near the coast). Postulate instead a cold current sweeping down from the arctic along the east coast, and you could somewhat justify the desired colder clime there.

The watercourses you show in the desert would go away if you take my mountain= rainshield route. The river over at the east of the savannah is probably ok - those mountains would get at least some rain. The river at the S of 'heavy forest' could be OK; might want to add another in that forest, draining to the north. If there's rain enough to grow a forest, it's probably wet enough for more rivers. Ditto your SE Elven forest - could use some rivers. You don't have to have mountains or hills to get drainage - the sources of streams there in a flattish district need only be dozens or hundreds of feet higher than sea level. Incidentally you can imply some terrain details with how you lay out your rivers - water flows only downhill.

Your rivers branch believably - lots of beginners / geographic innocents don't understand water flow at all. You're doing OK.

Your Madagascary island to the W could plausibly be jungle-ish. A main driver there is not just prevailing winds out of the west, but what latitude it's at. Equatorial latitudes tend to be wetter, 25-35 degree N or S tend to be drier, and then you get a bit wetter up to 60-ish degrees N or S. If you want this assemblage to be as big as say Eurasia, then go ahead and give us a scale bar that indicates that (assume a map projection where a scale bar has meaning). Then maybe draw an equator somewhere around the words Mostly Rocks, and indicate the word Desert is maybe 60 degrees N. That sets your desert N of the strictly lattitude-influenced dryness, but the rain shadow could maybe account for that. That would make your Tundra maybe a bit too far south - are you loving the overall shape, or would you mind stretching your NE quadrant further north?

Any of that sound reasonable?