I'd be willing to help too!

AH Maths is a difficult course, there's no doubt about it. There is a lot of content and you need to be able to do things quickly that would have previously taken a long time.
Now, like you say, you've never really needed to try before. Remember, it's the things you do when you are trying your best that are most rewarding - if you never had a real challenge then what would you really achieve?
It is certainly possible to get an A for AH Maths but you won't get it without hard work. And, as George says, the best way to make sure you know what you're doing is to do lots of problems. The
Supplementary Support Pack- Maths 1, 2 and 3 for AH Maths is available from LT Scotland which has lots of examples and questions to do (with answers).
Also, on
this page you should be able to get access to the Additional Question Bank for AH Maths (this has all old past paper questions from before 1992) - these would be very good practice. The page says you need to get in touch to find out how to get the file, but I think they'll allow you to get it. (If not, see if your school have old CSYS past papers.) I would advise against doing recent past papers as these are good for exam revision.
Another important thing is that if you keep getting something wrong then there is no point in trying more and more questions until you understand what you've done wrong and fixed it in your mind. If you don't know what you've done wrong, then your teacher will be very happy to help, as will I.
Just remember what you're aiming for and let that be something which gives you determination when you're feeling like you aren't making progress - you can do it!