Ignore whatever you know, and just either spend time thinking what you hear in your head or work with what you can come up with. Just archive ideas. If you play one riff that sounds cool play it again, but try and add some variation to it. Just paly it once, play it again but slightly different, play it again slgihtly different. Seems methodical and tiem consuming but it can be fun. Either that or find some way to jam over drums tracks with midi or a drum machine or whatever. Take ideas musically from your influences, if you feel limited by them and their styles find new music to play and learn from. If that bores you just sit there and play for 2 hours, or find some friends to jam with for 2 hours. Just play, don't think just play, let go of what you've palyed before, let go of waht you think you can do, what you think you can't just play music. If you like a particular key just play in it. I don't know whatelse you could do, take illicit drugs and then play something, stay up for 3 days stairght without sleep and rest then play. Experiment. Expand, Evovle, Don't try to write something great, try to write something that you could listen to over and over again.

Hope that helps dude.