I find I have trouble keeping my mind under hand. While in furthering the cause of any other pursuit, be it of exceeding importance or trivial vanity, my imagination grabs hold of the slightest diversion. My thoughts are often dominated by the most frivilous conjecture, such as the ability of a given piece of real-estate to survive a zombie attack. Sometimes I look somewhere and see not trees or rocks or benches, but AWP nests, foxholes, and spawn points. Perhaps even more disturbing is the fact that the rest of me seems quite capable of carrying on with my life even as the brain wanders off into absurdity.
Odd as this may seem to some, I think it is to be preferred to having never entertained such thoughts at all. Life, though it has plenty of demands, more than you could ever actually fulfill, is yet somehow incomplete without idle, fantastic, speculation. For myself, I live in as many worlds as I can find, and I revel in the escape they provide knowing, in the end, I have as sanctuary this pleasent reality.
If you want my advice, then, I suggest as much idle imagination as you can get. It's easy, free, fun, and ultimately you may find life obtains a kind of whimsy, just by thinking it so.