hmm when I get a block, depending on the project I usually do a word association with related words to the project. From there I then usually put those words into a google image search and see what the world has to offer about that subject. It may give you a different perspective on something you thought you knew about, also researching your subject usually sparks ideas find out every quirky thing about your subject something might pop out at you.
Now in a general sense for inspiration, it's like they said above observe the world around you. If you like something with a particular style take it with you, it might then give you ideas for later use. Collect things, studying good design and the whys behind it will teach you different techniques you might not know. Not copying the design mind you, but in the words of one of my teachers 'Everything has been done before, because it exists somewhere in the world, rarely is there some concept that is a new idea'
This is a quirky little blog about obsessively observing till it turns into a disease, but it's cute.
.Design Disease.