I told myself it is not okay to just lay things down on those places - it might seem easier at the time but in the long run I end up with a mess that feels overwhelming. I have been working on and praying for self discipline in these areas. Though I don't always keep them perfectly clean it has been much better than ever before. I do "mess up" every now and then but then I work pretty quickly to get back on track.
When I am tempted to lay something down that really should be put away somewhere else, I scold myself a little and try not to let myself be lazy in that way. Calling it laziness wasn't easy for me as I know I am not a lazy person and I hate that term but the truth is that it is laziness. Since I don't want to be lazy It has caused me to not want to just put things in temporary resting spots (that sometimes can tend to go long term) - I need to make a decision about where it really goes.
This has been helpful to me - hopefully this idea can help somebody else as well.
I would love to hear what helps you to keep flat surfaces cleared of in your house!