The easiest way to give yourself writer's block is to bridle your Muse by trying to come up with ideas. Your Muse is always coming up with ideas - just not the ones you want. If you try to limit the kind of material you will accept from her, she'll shut up entirely. So let your Muse run free. When she gives you an hysterical moment with a polka-dot elephant while writing a serious death scene, consider including it, perhaps as an hallucination. Give it a try, it might liven up your death scene! And after you've written it, if it doesn't work, then save it in a file for later use. It may seem like a waste of time, but your Muse will know she has been treated with respect, and will likely now give you just the idea you need.