I cannot tell you how many Sellers will not do the basics of decluttering or painting "interesting" color choices they have made as their thought is, "Buyers will look past it".

We've hired lots of new agents over the years and I strongly feel that its our responsibility to make sure our agents have all the information and knowledge they need to market and sell a property.To answer your question, in my opinion good marketing starts by working with the seller to make sure their property looks as good as possible (de-cluttering, minor repairs, fresh paint, staging.)  

You may be able to offer them a quick close if that suits their needs, or a closing on a date of their choosing that better meets their needs, which is something that a retail buyer may not be able to offer.You can also point out that they don't need to clean their house, de-clutter their house, stage their house, vacate their house for every showing and keep their house in showing condition constantly.

See if the de-cluttering makes it easier to see the possibilities.  

They are not new but you may not have read them.The Power of Habit - great book for understanding your own and other peoples habits.Hmm, most of the books I can think of have been mentioned on the BP podcasts.Buy and Hold by David Schumacher is great.The Life-Changing Magic of Tidying Up: The Japanese Art of Decluttering and Organizing - great for getting your own house in order.not a book, but a blog - Mr Money Mustache - great for getting your own life focused if Financial freedom is your thing. 

I think the concepts about decluttering your mind and setting up systems to not forget things are great.The most powerful idea he gave me was the concept of figuring out your next action step.

because it de-clutters the process and allows you to assign contracts MUCH easier.

Reason is is that there is a coloration between selling junk (decluttering) and moving.

Maybe you need them to do some other work around the house like clean the windows, shampoo the carpet, declutter, trim tree branches, etc.