[MarchHare]

If GH3 is your first Guitar Hero game, I really pity anyone who is trying to make the medium-hard transition. GH3 on hard is just absolutely brutal -- it's almost as tough as GH2 on expert. If you have it, try learning how to play with the orange button on GH2 first before trying to play GH3 on hard.

Also, another tip: if you're used to medium, you're probably in the habit of leaving your index finger on the Green button and then never having to move your fingers. On hard, the default position should be to have your index finger on Red, since it's stronger than your pinky and it's easier to have your index finger doing double-duty on green/red than it is for your pinky to do blue/orange. Depending on the section of the song, you'll shift your hand back and forth with index green/pinky blue and index red/pinky orange. With practice, it will come naturally to you when to switch hand positions.