Gawsh! I don't remember what it's like to be soo excited about starting in the service. Perhaps if I did I wouldnt be the cynical old git that I am!
Anyhoo, here goes. When you are at the school, PAY ATTENTION! Instructors only want to say things once - I know, I was one. Only answer direct questions - never chip in as you may be thought of as a smart-alec. Maintain your appearance - this goes a long way towrds demonstrating your self-discipline and motivation. Always give 100% on practical exercises. From personal experience, even if you are a clumsy so and so, the very fact that you don't give up and always give your best effort, the instructional staff will always be there to assist. If they aren't, they shouldn't hold the position.
I and my colleagues at the training school all agreed, the best recruits were the anonymous ones. They never got into bother but just got stuck in and did what was asked of them.
If you pick up an injury (sprains, strains, blisters, etc) - tell your squad instructor. Apart from the requirement to record/investigate/treat injuries, if you try to carry it without telling anyone, your performance will be affected and the instructors will notice. If they dont know you are injured, they will conclude you are just being lazy or not helping the team.
I wish you the very best of luck in your recruit course. Enjoy it. You should be able to look back on it as a happy time and with pride in a job well done.