This is how I designed a logo for our band Boomanova, with a lot of conceptual input by keyboard player and main guy Raha.
Real designers please look away now.
1. a lot of scribbles in my Moleskine, and in between university notes
2. recreating the first logos in Illustrator while scribbling some more during class
3. repeat process until you have 74 files with 1-30 logos inside each
4. cry
5. work on new logos in Illustrator and try to enhance some old ones (make them worse in the end)
6. choose some you like and present them in a nice way
7. talk to other people, get new ideas
8. discard all concepts, try more scribbles
9. despair
10. whatever, just take the one you like best, change it slightly and add flashy graphics
11. win red dot award, maybe?