Hey there. Congrats, youre embarking on a really worthwhile thing (that sounds really cheesy I know!)
Seriously tho, my few tips would be these.
1. Actually pay attention in groundschool (if youre FTO does groundschool). Always clarify something you dont understand (cos I wouldnt like to fly around someone who didnt understand something pretty integral, like altimetry!). Study the stuff well on your own as well. I know it looks like a lot, but you will get there and it'll be worth it.
2. Relax! God knows how many hours I wasted in my PPL by just being nervous all the time. I think its a well known fact that no info can go in if you're too nervous. If you cant relax with your instructor, try changing.
3. Know your aircraft and your checks. Understand what it is you're flying in (things like fuel systems etc), and certainly get emergency drills learnt by heart at some stage.
4. Enjoy! Too many people seem to finish their PPL without really enjoying it, and so give up quite soon after (typically within 3 years). The learning can be fun, but the bit after is soooo much more fun. Go touring and exploring, visit cities, have fun with your flying!
Regards
ETC