Emily got me this book for father's day about being a dad, written by a dad. It's broken down by month and tells you what to expect (baby's sitting up, baby's playing with toys, etc.)
The one piece of wisdom that has finally sunk in having read and re-read it is: babies get distracted easily and can forget what they were doing. It's offered in the context of "if you punish your baby after they've done something, chances are they haven't the foggiest thing what you are punishing them for."
This also works the other way. As long as there's no outstanding issue like hunger, illness, etc. you can really turn your baby's mood around by simply distracting him or her.
I've been using this diligently for the last week or so and it's come in pretty handy, apart from when Em's exhausted and just wants to cry cry cry.