A question with a thousand different answers!
Some more info might narrow down the options:
Budget in mind?
There's cost effective ways (cut and turned beam - down a few splines on the rear) - there's expensive, e.g. red nine replacement beam, air bags e.t.c.
Also - comfort factor?
You can slam it onto the floor for max drop but ride like a rail cart - or slam it enough and in the right way to the maximum whilst maintaining a level of comfort