Saving power tips for macbook

When i am in lectures and the teacher is rambling on about something that i dont have to note down is it best to close the lid of the macbook and leave it sleep or just turn the screen off? I am unsure if puting in to sleep and taking it out repeatedly would waist more battery than leaving it on.

Is it bad for my battery if i use it in lessons and get it down to 75% then get home and charge it to top it back up to 100% regularly?

If i leave for university at 9-00 but im only going to be using my macbook a few hours after should i put it to sleep or turn it off?

How often should I calibrate my battery?

do you have any Tips for keeping the macbook battery alive during school/college/university?

1) If the pause between 'taking notes down' is generally longer than say 5 minutes, then put the thing to sleep. Otherwise just turn off the screen. Cause each time the hard drive has to spin up and down, might cause some kind of wear and tear. Not sure though.

2) You can do drain the battery quite often. You can even drain it completely every time, as I do with my iBook on many occasions. The battery is still giving me 5 hours+

3) No need to turn it off. Just put it to sleep. Its a lot more convenient and every time you start/shut down the machine a lot of power is used.

4) Calibration is done only once. At least to the best of my knowledge

5) Stop dashboard widgets and any other unwanted processes that use up CPU. Other than that the usual screen brightness reduction should be good enough.

I read a few things on the Apple site about the battery. They say you should calibrate once every month or two just to keep it fresh.

Is there a difference between closing the lid and manually putting the laptop to sleep?

I ask this because the other day I closed the lid when my battery was around 62%. When I opened it up a couple of hours later, it went through the calculations and it was at 58%. I'm getting good battery life when my MB is in use so I'm not too concerned about having a bad battery, but that seems like a big drop for something that is in a low power state. However, I think I was downloading something when I closed the lid. Could that have contributed to it?