One thing that i've learnt to be very important recently is the need to make time to make mistakes. I'm not talking huge financial melt down but smaller scale mistakes within my drawings. When I get the chance to sit down at my desk to draw it's only one day a week, not giving me much time to experiment and play before it's time to pack up and go home. This is usually when I feel the pressure to make good work and this is usually when I make the work that I am least happy with.
By looking at my time in a different way, I save up any computer/admin jobs for evenings and spare mornings and use my one studio day to draw and play with materials. This has really helped me to ease the pressure and to just have fun with drawing again!
'Bad' work isn't always a lost cause either, I can chop it up, reuse it, collage with it or add new layers to it- it's not always a waste of time.
When I was studying on my textiles degree, my tutor told me that if I work fast to produce 10 drawings, on average 2 of them will be of good quality. I try to stick to this rule as a way of producing lots of ideas as well as getting lots of things down on paper. It's always better to have the quantity to choose from than trying to scrape 2 bad ideas together and to make them work.
Please let me know of any ideas that help you with this issue, I'd love to hear them!