Hi RYS!
I can relate to the frustration about spacing out. Please don't blame yourself. We only control our effort!! For me, spacing out is form of escapism. I my case I'm escaping the feeling of being a "failure" of not being the best bochur in yeshiva..
Getting mad at myself , for spacing out, was very counter productive - because it just gave me more reason to escape my shortcomings ("I cant concentrate for a couple of minutes = failure!). And often it woud lead to make "as if" I understood what my chavrusah said.
My new approach:
I just accepted that Im not capable of being focused all the time. Im trying - and if I space out thats ok too! Success should not be measured by the rank in yeshiva!! (Also see Dr. Sorotzkin regarding perfectionism)
Interestingly enough, since I stopped getting upset at myself. I space out much less.I also enjoy my learing much more. And my chavrusahs didnt dump yet. They are all very understanding when I say "Sorry, I spaced out - do you mind saying that again?"
Its hard to accept, but as soon as I did, it just went upward.
We only can give it our best and thats all that counts!
Hatzlacha!
I just realized: What would swiss cheese be - without all the holes