Hello all! I'm creating a homebrew world for a campaign I will be DMing soon and I could use some advice. I don't really know topography or map making at all. I'm only able to even try because I have Wonderdraft which helps make it easier. I've made the shape and added some mountains and a few details but it still feels like it's way too empty. I'm not worried about cities or settlements yet, and I know a lot of stuff I'll come up with as they explore. I don't need every detail but I feel some lakes, rivers, and more forests are important. I have ideas of features I want like marshlands, and I know hilly areas and plains are important..

I just don't know where any of it would go! Any help or suggestions for figuring it out would be great! Here is a picture of what I have so far. The large black colored part is story related and completely empty for now.

I recommend to make very first versions to physical A4 paper with squares because scaling is so much easier to do later - no matter what computer programs are used. If you have Dungeon Master's Guide there are great advices for scaling the world size. (Chapter1,  page 14)

Check video content of WASD20: https://www.youtube.com/watch?v=zVDmrujnSag

I also recommend to start the campaign with province scale map instead of whole world / continent. (One A4 page, 1 square or hex = 1 mile)

Some more rivers would make sense. And a note on rivers - rivers come down from mountains, not in from coastlines, so your current big river doesn't make sense topographically. Other smaller rivers will sprout out from this river as well. Remember that civilization sprouts around reliable bodies of water, and that smaller settlements will pop up everywhere.

Consider wind currents and temperatures. Mountains near coasts often have a feature where the side near the coast is lush jungle and the other side is arid - I forget what this is called. Don't be afraid to add in more forests, even smaller ones. Unless you have insane mass-deforestation, there should be much more woodland. Consider also other features such as swamps and deserts. Use different colors to represent these. 

If you're stuck for ideas, take a look at Wonderdraft's Reddit and see what other people have posted on there for their own maps.

Thank you for advice on this, I decided to focus on the smaller portion of this continent, just the one kingdom, and have been working on it for a bit.

Also that large cut through the continent isn't a river it's a canyon that leads out to the ocean formed because of an event in the worlds history. 

So I've drawn a campaign continental map for (hopefully!) my homebrew stories for the foreseeable future. I tried to put hills around mountains and forests around rivers where possible, and also put in a few plains. You can leave parts of the map blank if you need to! For one part of my map, I put in a lot less cities and civilisation, as that stretch of land was plagued by tidal waves and extreme weather, leading to periodic flooding and mass migration out. Just some ideas, they might not even be needed anymore as it seems you're doing pretty well anyway, but hope they help!

here's a good resource for additional cartography assets - hills, forests, etc.  if you plan on selling what you're making, make sue you filter by license and don't use the 'NC' ones...and follow the rules of the other licenses as well.

https://www.cartographyassets.com/

I made a portion of the map that the players are in with what I could, but having somewhere to get a lot more assets will help when they start exploring outside the starting area. Thank you. ^^