There are many solutions. (It all starts by cleaning out your camera! Dust on film at the time of photography creates black spots in your images.)
If you process your own negatives:
Mix chemicals thoroughly with filtered water.
Use chemicals before the manufacturer’s recommended maximum storage date.
Follow the replenishment and storage guidelines precisely.
Maintain temperatures within a very narrow range.
Use a hypo clearing agent on black-and-white films to reduce wash times.
Use filtered wash water. Keep the wash temperature as close to the process temperature as possible.
Use a wetting agent before drying.
Use a CLEAN film squeegee to remove excess wetting agent or stabilizer before hanging film to dry.
Use a weighted clip that holds film straight as it dries.
Dry film in a dry, clean room where air does not blow.
DO NOT dry film with a hair dryer!
Handle film with white nylon gloves.
Store film in archival polypropylene pages or NegaFile glassine envelopes.
Store 35mm and 120/220 roll film in strips of at least two negatives. Otherwise, handling is awkward!
Invest in proper cleaning tools:
Giottos Rocket Blaster squeeze bulb blower — first line of attack for loose dust
StaticMaster Brush — next choice for clean film — reduces static so dust wipes away
PEC Pads and PEC 12 Photographic Emulsion Cleaner (Both are from Photosol. Use on stubborn grit, goo, tar, fingerprints, etc.)
Ilford Anti-Staticum Cloths (last resort)
Be gentle! Film scratches very easily.
Keep your copy rig spotless! If it is metal, electrically ground it.
Consider temporarily covering nearby walls with black landscaping plastic ground cover. CHARGE it by rubbing it with a thick wool sweater. This statically charged surface will attract the dust from the air nearby.
If you haven’t changed your HVAC filters in a while, replace them with high quality filters that are labeled “Allergen Reduction” or some such.
I worked in a huge photo lab for over 30 years. We had additional commercial solutions that didn’t work as well as some of these, back when we processed several thousand feet of film every day.