I just mix my first paint layer with Liquitex Ultra Matte Gel and lately Ive been using Golden Satin Glazing liquid and I also have some Golden Liquid Matte medium coming in the mail, on advice from @anjsmiles. After that first layer there is no problem with the paint not sticking. Like @rainbow I only use a sponge to pat around and mop up drips and then I use the Kabuki brushes as well. I use a brush to put my paint on, then the sponge a bit and then the big brush to blend it in. I mainly use make up brushes, they tend to work better, all the mop brushes I have bought shed too much.