Here are some tips:
Use the best cassette deck you can. They are not all created equal. Clean the transport and the heads thoroughly.
Use the RCA outputs if possible. Generally the quality will be better there than the headphone jack.
With noise reduction try to determine if Dolby B, C or DBX was used. Most likely Dolby B was used. Listen and compare the sound with Dolby B ON or OFF. Sometimes it is better to leave it OFF and gain the extra high end. The times it works perfectly with it ON is if you are using the exact same machine that recorded the cassettes. If you feel the high end is dull and the Dolby B is over compensating then leave it OFF. That sounds better than having it ON. But if the music sounds good and normal with normal top end present with it ON then leave it ON. This is one of the most difficult aspects to cassette transfers, determining if Dolby needs to be ON or OFF while transferring. Use your ears here!
Dolby C is a much more viscous form of noise reduction. Playing back with Dolby B on a Dolby C encoded recording still won't sound right. You will hear it. Hopefully it will be a Dolby B encoded recording. There were far fewer Dolby C machines around.
Set the levels reasonably high coming in. You will find once you set the loudest point, the music will rarely go over that.
Try using EQ to perhaps improve the resultant captures the best you can. Do not mess with the sound on the way in, it is a mistake. Connect direct from the cassette deck direct to the audio interface. If you have to control level maybe run it through a very neutral level controlling stage.
If all else fails send the tape to me. I have a seriously expensive Sony deck that sounds like a million dollars with a super precision dual motor/capstan transport and with Dolby B and C. It also has all sorts of EQ options for different tape types on playback too which can be helpful. I will transfer it for you.
Thanks for bringing it up. I have got a lot of cassettes that were recorded with a very nice machine and they still sound amazing. I should transfer them too.