The main variable, I guess, is your budget.
1- Adding a spacer ($)
2- Changing the front coils ($$)
3- Putting a lift spindle ($$$)
4 - A combination of the above ($$$$)
1- Adding a block ($)
2- Adding a add-a-leaf ($)
3- Replacing the spring pack ($$$)
Of course, generally speaking, the ride quality is supposed to be better with the higher cost items but you really might not need it either.
I would suggest contacting Boulder Offroad Vans
or Weldtec Designs
and having the work done at their faciltiy.
Also, if you're going for the simple options, just about any competent local suspension shop can do it but be prepared to become knowledgeable beforehand just to make sure they're doing what's right for you.