I lived with Kidney disease for 24 years before they failed.  Low/no
salt, control of BG and blood pressure, low protien diet, and low
potassium are all standard and worthwhile efforts.
 Things I've learned since the transplant (and no one told me
before), my x-plant Doc has me on 1200mg of omega 3 fish oil, 3 times
a day.  He says it is now well accepted that the omega 3's help
prevent, and slow the advancement of renal disease.
 When my creatnine hit 3 is when they got concerned, when it hit 8
they put me immediately on dialysis.  I have a good friend that lived
for a year at the 4-6 range and never went on dialysis, she went
straight to x-plant (had a twin sister willing to save her life.)  Now
it runs about 1.4 and the docs are very happy.
 Also avoid high stress, it can have an effect on the kidney health.
During my years the only time I had serious bouts with the disease was
after things like houshold moving, getting sick with the flu and
trying to 'tough it out' rather than getting lots of rest and fluid.
etc...
 Above all keep it monitored!  If you have the insurance and the
doctor agrees, get regular blood tests and talk to a nephrologist.  I
found a lot of doctors 'think' they know all they need to about kidney
disease and I had one experience that put me in the hospital from bad
doctoring directly related to ignorance about kidney disease.
 Good luck and best wishes.

Sean