Fake Out helps alot, yeah. (Or so I would imagine.) It's next good move is Night Slash, which comes at levels 37/43--and there are big statistical trade-offs for waiting to evolve Purloin.Okay, I'll admit this. The last few levels in the Choroneko stage are a pain in the arse.
Teaching Thief to it helps though, as if you are lucky you'll steal a healing berry, use it, and then get a speed boost with Unburden.
At Lepardas, it is much stronger than most things you can get at that stage. I got mine in Hiun and had no problems with it from then on.
As soon as you get Fake Out, use it. Hone Claws is good as it makes Fury Swipes 100% accurate. Slash and Night Slash allow you critical hits.
With all of that, I never had a problem.
In breeding it though, you can make it a potent pokemon. Foul Play is great for an under-leveled Purrloin/Liepard (wherever the daycare center may be, I don't really know), and Encore and Yawn can allow for decent set-up. Covet is also better in some ways than Thief, having the same power as Thief without STAB, while also having more PP.