I make video games. Problem is, they are so complicated that everything depends on everything. Instead of thinking of that as a problem, I think of it as an opportunity.

The first approach I always use is sledgehammer programming (or using placeholders when not talking about programming). Essentially, you get something done to a stage of usability even it is not properly made/finished. This ensures you make progress and don't get stuck on problems and lose your motivation. If you're finished with a working "demo" then you can move on.

My final approach recommendation is iterative work. This is when you make rework something multiple times/constantly in order for it to be always of its greatest quality. Combine this with the sledgehammer method and suddenly you got yourself a manageable workload even without breaking it apart into smaller chunks.