My suggestion could be entirely placebo but I'm certain it had an effect for me.
I felt the same thing as you, like my game was smooth but it could be better, little micro stutters and things. I tried everything to fix my fps: changing configs, removing hud elements and crosshairs etc.
The one thing that fixed it for me (I'm fairly certain) was getting a new mouse. My old intelimouse must have been on its way out because when I got a new mouse my game felt smoother, those micro stutters felt removed.
Another thing I'm kinda thinking affects it is, as others have suggested, internet. My game felt incredibly smooth all lan but returning home to my less than brilliant internet definitely made my game feel less smooth.