I used to practice mirror writing. I got quite good at it.

I think that every lecture can be interesting in some way If you listen carefully (at least for me). If you really are not interested in any topic,just think about something pleasant (rely on your imagination).

draw a picture, or go online, here on italki. * if you have wifi at school

Less eat before the lecture. After a big meal you can feel sleepy. I hope this can help you.