To avoid stress, I first determine from a huge list which projects are going to have my attention. All the others gets trown into the backlog (like in scrum) and I totally forget about them.
Then I flesh out each project into the phases that I'm going to do. I.e. Project setup, get engine up and running (irrlicht for instance), do log system and I try to fit those roughly in order of appearence. You can't plan everything ahead, but as new tasks pop into my head they get added to the list. The idea is to empty your head, since every task in your head will add to the total stress level in your body :)
Now you have your head empty and a list of ideas as well as a rough bullet point list that details the order of implementation. (could be research points here too tho)
You now have an overview of all your projects and you have a handy list of smaller tasks you can check off when completed. This gives you a great feeling of accomplishement when you are able to take a task of the list. It also gives a handy overview of your progress.
And why have multiple projects instead of one? To expand your horizon, tax your brain and most importantly: to avoid burnout when working on a single task/project.
With this setup you can freely move between subtasks and projects if you don't feel like working on a particular task. Sometimes coming back later with a fresh perspective (from working on something totally unrelated) is what it takes to solve a task that you previously found too hard or boring.
It's just like having 2 kids. You have to plan your life much more than when you where just two adults, but that doesn't mean your life gets more boring :)