I don't. I realise that I am being extremely unhelpful, but I have the same problem. Most of the time I have GREAT difficulty concentrating. I often find my mind wandering in a thousand directions and sometimes I just feel like my brain recieves data but is unable to analyze it There are, however, times when my mind is suddenly crystal clear and I usually try to catch up with things in these periods. It's not a foolproof way, but it seems to be the only thing that works for me. Trouble is I get panic attacks if I try too hard to learn stuff when I can't.