In no particular order:
Replace worn out body mounts.
Install "missing" body mounts.
Install rear seat braces.
Install front frame braces.
Install front triangulating brace.
Install fender braces.
Replace worn out shocks.
Replace worn out springs.
Replace worn out front end parts.
Larger sway bars.
Substitute, for example, polyurethane for rubber.
More "aggressive" tire/wheel package.
And on and on...
Ummm, careful what you wish for?
strike