Share your tips, ideas and what not to do's

It seems a good idea for people to share a few tips and have some fun experimenting with ideas. Maybe it would also help if people shared their trials too, because we can learn from all kinds of things... We learn by sharing, copying and generally making mahem in a studio/kitchen/garden shed.... None of my 'failed' canvases go to waste. I use them to experiment upon after sanding down with fine grade wire wool/sandpaper, then put on a couple of coats of coloured gesso. I use these for lots of practice and fun playing with things that I am unsure of. I use powdered pigment to colour my gesso prior to any underpainting. I generally mix an olive shade which is nice for portraits, making skin tones warmer, etc. I leave canvases white if I want to create very very bright blues, whites etc., though you probably all do similar with your canvases too... I sometimes use those almost damp kitchen flat sponge cleaning cloths to underpaint large areas in acrylic paintings. I use them for painting too! I think that they are by spontex.. They are about 8" square. It is fun to do and I can get fabulour wash effects using them quickly over dry acrylic, toning the paint to whatever I have decided... Gosh, I could waffle for ages and I bet you all have much better tips and ideas! So tell what you do and perhaps we can all ask each other questions too. Maybe we can help each other along the way in our painting journeys...