Like Shonsteez said, creativity cannot be forced. And creativity is dependant on mood too.
Sometimes I get stuck into a method of doing things and I find I get pretty bored quickly, so I take a couple days off and come back fresh, and try new things.
My ratio goes up and down, sometimes I can bang a few pretty decent beats out, other times I just cant get any out. I think thats a part of being creative, sometimes it works other times it just dont.
Just keep at it though and when you do get in the zone you will find your ratio getting better and better.
Just keep practicing and practicing. Its the best way to improve.
If you get into a creative block, just listen to different music, you will be dying to get back onto the production in no time.
I cant listen to music anymore without wanting to get straight back into production.
1 phat drum fill or drum samples in a track and I almost piss myself with excitement.