Here are a couple of tips that were given to me by Meg Edwards during some tele coaching.
Projects lists should only contain those things that you need to deliever on in the next 9 months.
Deliverables beyond that belong on your 'Someday / Maybe' list and can be turned into Projects when they fall into the 9 month window.
If you make sure you include a review of your Someday / Maybes in your weekly review you wont miss the projects and you can get them off your mind.
Next Actions Lists should only contain NA's that you plan to complete in the next 2-3 weeks. Other actions that I think of during my weekly review are written and stored with Project Support Material and I can turn them into NA's when I need to.
These two simple things have helped keep my NA's and Project lists under control