Re filtering: I think this really depends on the road. Around here most roads have bike lanes. I stay in the lane and move up to the light.

Some no-nos I haven't seen yet:

Don't forget something at home you need at work (e.g. your pants). I found it helps to develop a routine (I pack my stuff the night before).

Don't forget to check the weather. Around here a day can start out nice and turn nasty pretty quickly.

Don't forget to take it easy: Daily commuting can take a toll if you are hammering to work every day. Slowing down only costs a few minutes, but makes a big difference in fatigue level.

Paul