Perhaps ironically, I feel like my Android phone (Samsung GS3) helps me manage clutter much better by letting me arbitrarily arrange my app icons. As a result, each "screen" in my home screen tends to be less than half full of apps, organized in rows of arbitrary length by type (ie. Yelp and Opentable together, Dropbox, Drive and Evernote together).
In contrast, on my iPad, the enforced layout of app icons makes each screen seem cluttered and muddled.
I wish at work I could just focus on one thing, my job invites the clutter of too many things pulling on me. I've always been able to multitask more than most but it's always at a cost. If I can work on one project all day I am far less exhausted than working on many different things on the same day. One day recently I worked on 4 apps back and forth. Our brains are not made for that kind of twitchy thinking. It's not just physical stuff that makes up clutter.
Getting Things Done is so comprehensive in this regard it would be nice if related articles explicitly referred to it. It's a great reference point, in my opinion.
I found it very ironic when I tried to read GTD that it actually has a very cluttered layout. Every page was littered with little side boxes explaining something. I found those so distracting that I was unable to focus on the main text.
So GTD definitely isn't the solution for everyone.
In contrast, on my iPad, the enforced layout of app icons makes each screen seem cluttered and muddled.