I find that having an actual chapter outline while I'm writing helps keep me on track. This doesn't mean that my characters don't go off on a tangent or add more to the story, but at least I have a basic idea. Each of my chapters is about 1000 words which means the word count of my novels is easy to track.

This is the outline I use: https://docs.google.com/document/d/1v9oUPNVQ7hCO3WksRDcAH77c9eDPeQJ4DK4Ke1qlXMU/...

I tend to write in alternating POV (choosing two characters to follow).

This is the one I'm prepping now (as you can see I've added a third person, but he's not every third chapter).

https://docs.google.com/document/d/1uZzP29QVVUyVts_c6EO-PzLO0lfseILRqhPX-IXp4RM/...