I've done a couple different methods before. The first being to take your coated paint brush, wipe it off a bit so it's not totally saturated then run your finger through the bristles towards yourself. The second method is to hit your paint brush on another object like a screw driver or a wood block so that it flings the paint onto the object or canvas.
Maybe a weird suggestion, but check out miniature (Warhammer) painting videos. There's a boatload of techniques for different effects, some of which, like paint splatter should translate to most types of painting.
Paint splatter follow-up I've tried both techniques that @MisterYuck mentioned in the past and I think they both have promise. For the flinging of paint from running your finger along a brush, I've actually found a toothbrush works better than a paintbrush. Tapping a paintbrush on another object works but I found I never had the control I wanted. I think both methods just require a lot of practice to get consistent results (like with anything I suppose). I did also check out a few videos. The only new thing I tried was using an airbrush to blow air onto a loaded paintbrush from a few inches away. I think I like this method the best. If you hold the airbrush close to the paintbrush you get more fine splatter, further away big splatter. Definitely requires practice. I think my only real finding, other than each different method requires practice, is that using vinyl paint for splatter is probably a bad idea. I'm sure some people do it successfully...but if it is too thinned, it will eat away at your existing paint job and look bad. It's way safer to use acrylic paint. Since your primary paint app is probably done before adding splatter, acrylic makes the most sense.
Try a denture brush BTW - it's like a big cartoon toothbrush on one side and a smaller detail one on the other side usually, they are very useful cleaning / splatter tools. Plus they almost always have them at dollar stores.
I know this is a V-Color thread, but god damn I just broke open my Vinyl Wonder paints for the first time this afternoon and it made me almost weep from bliss. I didn't see a Vinyl Wonder paint thread but there friggin needs to be one because this viscous chemical needs to become a household staple.
