While the available search options weren't perfect I found I needed a list to simulate how I used to use the "Notifications" bar from the last version of the Android App. When I didn't get to something right away, it would stay in that bar to remind me to get to it later. With the removal of that bar I created a new smart list to try and capture the spirit of that and using a home screen widget I get a very quick way to check nearly due or slightly overdue tasks.

Here's how I started:
status:incomplete AND (due:yesterday OR due:today OR due:tomorrow)

Then I thought it would also be nice to be reminded of tasks I added today, and are due "soon":
status:incomplete AND ((due:yesterday OR due:today OR due:tomorrow) OR (added:today AND dueWithin:5 days))

Once I had used that list I thought it would be good to also see stuff that has a specific tag but could be done at any time. Specifically I use tasks to remind me about the expiration of a Groupon that I've purchased. I use the due date to show when it expires, and I tag them with #groupon. Adding them to this list was easy and again gives me a quick glance at things that might be a far future due date, but I also want to be aware of as I can do them now.

status:incomplete AND ((due:yesterday OR due:today OR due:tomorrow) OR (added:today AND dueWithin:5 days) OR tag:groupon)

Now I've got a smart list that shows me anything I missed yesterday, and due within the next couple of days with some specific pieces of information. If RTM adds the ability to search backwards further, I would have loved something like "dueWithing:7 days ago" to be able to go back a few days further than yesterday, but it's a smart list I use several times a day now.

I hope it helps you create the right smart list for you!