Here is the process I use:
1 Get bottles as cold as the beer, even colder is OK.
2 Turn off gas to keg, bleed off head pressure in keg.
3 Turn CO2 tank regulator down to 2 psi.
4 Turn gas to keg back on.
5 Fill bottles.
The two things that I've found that make the most difference are: getting the bottles cold, and using the lowest psi that will move the beer from the keg to the bottle.