Generating ideas is about getting a lot of ideas. 

Accept that a lot of them will be really bad...if you hold them back, they just block the way for the brilliant ideas...

In Step 2 you generate as many ideas as possible based on you focus question from Step 1. Quantity matters. 

Tools for kickstarting the ideation process are numerous, so feel free to use any tool you know. But here are a few classic examples.