I like and agree with what others have said here. Having a good set of "contexts" is important and narrows down the list of things to consider at any given time. I find it important to look at every one of the pending actions in the weekly review; that keeps them all enough in mind so that through the following week I know there isn't something lurking in a corner that I should be doing but am not remembering. That helps a lot.
I try to stay calm about having lots of things on the list as possible Next Actions - it is well over 100 for me. I am learning that it is not a burden, because I can only do one of them at a time. I will never get them all done, but I will be doing the ones that matter the most. Once I have narrowed it down by context/location, time available (is it a ten-minute job, or something that is better if I can work a couple of hours on it?), energy available, and priority, it is usually just a half-dozen or so things. If one of them really catches at my mind as "I should do this right now instead of that," I trust the hunch and go with it. If not, I will often just start at the top of the list, as Oliver said above.