Peace_Lover,
Welcome to Army.ca. I sure you already did a search on this topic....so I'll weigh in here with my advice.
During the course you will be "fed from the fire hose". Pay attention in classes, ask pertinant questions to the DS, and ask for help if you require it.
Above all else.....remember TEAMWORK.
Get together with the rest of your course candidates and get certain things sorted out. IE: kit layout (your DS will more than likely have a layout done up, you just have to lay it out the same), cleaning of washrooms, bedspaces. Don't procrastinate on chores....get them done quickly and correctly so you can free up some time for yourself and the rest of the course. When it comes to PT...work together and help out the weaker in the crowd.
...and if you have any time to yourself, remember:
Enjoy yourself ;D
As for preparing yourself mentaly and physically....don't worry. The courses these days are geared to teach, not to screw you around like they used to when I first got in. They'll put some pressure on you, they have to....it's the Army way.
Physically....well...that's entirely up to you. Don't stop, do your best and show to the DS that you are improving and you'll be fine. Worse comes to worse train in your off time. I've met alot of troops over the years that couldn't run to save their own skin....now they all blow by me. It takes time and alot of perserverence to become a "Gazelle".
Good luck
Regards