To my experience, writer's block is usually an indication of some kind of problem. I usually combat writer's block by approaching whatever scene is giving me trouble in another angle. Usually that gives me a start, but if it's not enough, skipping to the next scene and working backwards from there sometimes works. If it's a particularly nasty block, I revisit character designs, outlines, and planning sheets. I look for the issue. If there's none, I table my work for a couple hours. There's no use in stressing over it for several hours at a time if it's just not working. That's a highway to Migraine City. If nothing has worked, sometimes writing short scenes completely unrelated to the story helps me. I've written plenty of memories between Gwynn and Zoey that never made their way to the final product. Same with Sam, Jay, and Oliver. Drawing helps, too, as does listening to music. I always listen to music when I write, and sometimes I find I need a VERY particular mood in order to execute a scene just right.