I just read this post in iHanna's blog, a long time favourite blog. She talks about practicing drawing in her art journal. I think it is a great idea.
Drawing is something we all did as children. It is like dancing or singing, you don't have to be good at it for it to give its pleasure. Just like how we sing in the shower, or dance when we are by ourselves, try drawing in your art journal. No one else has to see it. Don't compare it to anyone else's drawings - most people who are good at drawing have been doing it for years and years.
In my art journal, I try to give myself permission to do 'bad' drawings. I find this challenging as much of my identity as an artist is based on 'I can draw'. This can be very limiting as I stop myself from just fooling around.