Are you using default or custom sliders? If you are using default sliders I highly recommend trying some custom sliders.
This is a good place to start. I have found
Bill's v3 Realism Sliders the most realistic and competitive, but if you are new to the game they may be too difficult. As far as tweaking your sliders Bill also did a great job testing and researching what each slider actually does
here. It is a long read but definitely helps in tweaking sliders to your personal skill level.
Aside from sliders how do you play defense? Mainly coverage or blitzes? Personally I run a 3-4 and blitz all kinds of different ways which really puts heat on the QB creating sacks and picks. I also blow up some running plays. Hope this helps.