First of all, hello everyone. I'm very new to drawing maps and this is my first post here. Recently, one of the characters in a Pathfinder campaign I'm in recieved a map of the world we're in. I then thought, 'Wouldn't it be cool if that was made into a real map?' and so I asked the DM about it and he really liked the idea. So I started making some sketches but I got a bit stuck. I'm not very familiar with cartography or geography so I'm having a bit of trouble with laying features out properly and making the map look good. Here's what I have so far:

This is the western continent and the most inhabited and explored land in the world. I imagine it having a climate similar to Europe, being very cold in the North and much warmer in the South. The only requirements the DM gave me is that there be a mountain range in the northeast and a chain of islands on the eastern side. He said it should be roughly the size of Australia.

This is the eastern continent and is much less explored. It's mostly desert and mountains and roughly the size of Africa. There's a mountain in the centre with a river that flows from it and goes to the west coast with jungle extending from the river.

I'll eventually be moving these into Photoshop, merging them, give the map an aged look, etc. So, I've been having trouble with placing geographical features so that they look right and make sense. I also need to figure out where to place country borders. (The east continent is to have a maximum of six nations and the west will have a maximum of three.) Does anyone have any tips/advice? It would be much appreciated.