Only things mentioned here are the changes to the current route

Kill a hoppip on way to rival if you see one

Always skip bitter berry

After leaving the center, do r32 manip which ends after Anthony, skip przberry 

Azalea mart 
  Buy 3 potion, 3 super potion, 5 repel, 3 antidote

Rage rocket 2 and 3

Water gun Caterpie/weedle guy

Talk to Benny- water gun, water gun + rage(rage), rage

You are lvl 20 for miltank