- Question the work
Always be questioning whether the thing you're doing really needs to be done. Is there a way to not do it? Is there a way to do something better instead?
- Park downhill
Before putting a project or incomplete task away, make notes of what the next thing was that you were going to work on. This lets you bypass that 10 minute orientation getting back into the project the next time you pick it up.
- Keep a single todo list outside of your head
You can only have one master, so keep a single todo list in order of priority. Whenever something pops up on your radar, put it on the list in the right spot and immediately forget about it. Check the todo list a few times a day to make sure you're working on the right thing, and whether you need to communicate that something low on the list won't get done in time. Aggressively try to weed out the list and remove as many items as possible, preferably by not having to do them (by reassigning, by replacing or by reprioritizing).
Benefits: (1) not forgetting to do any work, (2) free up your mind to focus on work instead of meta-work, (3) clear priorities, (4) detect early when work is going to get delayed.
To combine this with park downhill I either keep the per-task notes on what to do next right in the list (in a details field of the todo item), or I keep it somewhere else and have just a single top-level item "finish X" in the master list.