For a while when i got bored at work I would open 2 tables and try to guess their hands by the river.
It sucks when there is no showdown but it passes time.
If you play 2 tables you should be able to look at every decent sized hand and work on getting their hands in the correct ranges.
ALWAYS THINK OF RANGES. it helps.
If someone opens from UTG+2 and their PFR is 5% their range is 99+, AJs+, KQs+, AKo
If they are still showing alot of strength on a certain flop you can restrict their range even tighter.
Pokey has a great great guide on hand reading
here. Its unbelievably long but worth it.