How to make Spinning more of a challenge?

[Gobias]

I am brand new to spinning and love it! When I started Cycle Max I set my resistance and pedal stroke speed to fatigue but those settings became "easy" for me (well, "easier"). I then upped the resistance and pedal speed and it became a challenge again.

My question is, to make spinning more of a challenge, am I doing the right things? Upping both the resistance AND the pedal speed at the same time? Or do I up just one or the other? Does it depend on whether I am sitting, standing, or hovering? I notice when I am hovering, I can up the resistance but I am unable to up the pedal speed much (makes me feel unstable). And when I am sitting, I can up the pedal speed, but am unable to up the resistance much (I will go super slow). When I am standing I am able to up both.

I don't want to do the wrong things and end up with a knee or hip injury.

I have to say the results with spinning are fast. Wish I had started spinning years ago.