As seen here I have a few canvas bags I bought a while ago and hadn't done anything with so I've been trying to come up with a few ideas to jazz them up a bit! I didn't use fabric paint for this but acrylic seems ok, I just ironed it once it was dry and will make sure I wash it inside out. Also as its only a bag I wasn't concerned with it being stiff, where as with clothing you'd want it to be soft.
Firstly use masking tape to mark out your pattern, this will work as a stencil. I cut strips of tape in half for the smaller parts of the pattern.
Then fill in all the shapes with paint. Watch out when painting over the tape and make sure its flat down on the fabric so you don't get any paint under the tape and mess up you're lovely design.
It doesn't take very long to dry so be patient! I had to distract myself whilst I waited and as soon as it was dry I peeled the tape off. I wasn't sure how this was going to turn out but I was pleasantly surprised and I am definitely using this next time I go out.