Yeah, my desk isn't the cleanest (I thought this was a safe space! >.<). I'm using a laptop that routes to an external GPU which gives me the ability to add 2 more monitors.

Not the best setup but it works for me right now. 

I feel confident in saying that multiple monitors are a must for anyone trying to create something. 

As you can see from me, I have a landscape style monitor (the long one on the left). This is great for displaying your code withing an IDE such as the one that Gamemaker comes with.

While you could do this on a normal 16:9 monitor, it is very convenient to view the entirety of a script without a whole lot of scrolling. 

This means my other monitor on the very right can just be used to display the game editor itself. Again, super convenient and saves me from jumping in-between my code and editor space.  

This can turn into a pretty huge debate in terms of what works best. The reality is that you can never have too many monitors :D! In all seriousness, the multimonitor setup is extremely helpful once you've got the set up.

If you're interested in this kind of set up here is some equipment I'd recommend. Remember, you don't need three, necessarily. Two monitors will take you really far!