This is what I usually do: In the poses Library I make a new directory/library which I give a own name like "My poses" or whatever you want.( if you start with a ! it will on top of the pose library) Then I go to the particulair frame I want to copy and press the add to library button (the  "plus"sign). You will be asked for a name to give to your pose set and you have to select a subset, if you want the whole scene to be copied, you select everything, otherwise you select only the figure(s) you need. After that you will be asked what frames you want, you want to copy only one pose so you select single frame and you enter the frame number you need. (I always give the same start and finish number, but I don't know if that's necessary for single frames) Now you have your pose you want to copie in your own library, go to the destination frame and apply your pose.If you don't need it anymore you can delete it from your library. In this way you can even copie sequences of you animation to another part of you animation. If you have a kind of walking loop, you can even use it in walkdesigner. The only thing I have on my wishlist is a way to reverse a sequence, but that's perhaps for someone with more pythonskills.

-How can you improve things when you don't make mistakes?