1] Do not fill the reservoir to full. [avoids boil over coil contamination ]
2] Run on "low" setting if the distiller has one [avoids boil over coil contamination ]
3] Remove any post distillation [output] filters..they add contaminants for flavor
Pre-filters are OK
4] Use the purest source water you can. [Rainwater?]
5] Discard the first bit that comes out [volatiles vaporize first ]
6] Avoid boiling the reservoir dry and rinse away any sludge or minerals left behind before it dries.
7] Periodically soak the condenser coils and any other relevant parts in white vinegar and rinse well with distilled water.