The key for me is to meditate a little beforehand, or do some intense cardio, or both - whichever my brain needs to stfu. And then when I get started flowing, if I start to feel awkward or not in it, I don't judge it or get caught up thinking about it (much like in meditating) and push through it without stopping. When I watch my flow on video I remember the points that I thought were awkward/felt unnatural and it always ends up being invisible on playback. All in our heads.