You cant force the creative proccess... It has to come to you
You cant just lock yourself in a room and red bull up some great ideas. If that worked, then everyone would be prolific creators. What you need to do is just stop trying so hard. If you have enough experience, knowledge, and exposure, the ideas will naturally come through your practising and performing.
Quoting one of my favorite magicians, John Archer, "If you want to find something new, stop looking" Though he meant it as a joke, this does apply. Stop trying so hard. You will find something new if you just let your mind flow.
Let your creativity flow, instead of just going over every hard move you know, how bout setting yourself some challenges:
"Wonder how I could achieve this effect..."
"What can I do with these few objects..."
"I dont like this move/ trick. How can I improve it..."
"What hasnt been made yet?"
"What has been made, has many variations, yet can still be improved?"