I would also second using Dokumol (try it at 1 + 6 at first and then increase concentration from there) and developing for a minimum of three minutes.
Originally Posted by Guillaume Zuili
Selenium toning the negative is also a good idea and you will not ruin your negative by doing this.
Also, check if your safelights are really safe as they can contribute to a softening of the image.
If all of this still does not get you what you want, you can (but be very careful) also add some Caustic Soda to the developer.
Best of luck,