I tend to disagree with the idea that "it's all been done before".

If all you listen to is rock or pop or whatever then naturally everything you try to write will sound just like your influences.

Try listening to a form of music you'd never think of even touching with a 10-foot pole and take your rock mentality and apply it to this style. Guaranteed you will start thinking in new ways.

Take that chord progression that you think sounds like something else and put a different rhythm to it (i.e. funk it up).

Try combinations of effects pedals. A simple tremelo effect can render even the most familiar licks unrecognizable and start to sound like something new.

There's a million things that have yet to be done in music, just don't be afraid to step out of the familiar territory because of what someone else might say.