Simple question, and simple answer. It ain't easy! Smuggling artifacts is tough. Try staying out of the trade lanes and use your burners to take patrol routes. If anyone searches you and you don't drop them, you're toast. Best is to take the loss and drop them, and live for another time. If you are near a planet or base, and they catch you, immediately dock at the base or planet. You have some time before they turn red on you, and you can usually get into the dock before they nail you. After you've sold them, they'll scan you coming out, and your cargo hold is clear and they'll let you go.
There are plenty of non-smuggling commodities to make good money on. Check out the spoiler forum for suggestions on how to make good money that way. This way if you're scannned, they'll leave you alone. That is, of course, if the faction is friendly. If they're hostile, they'll shoot you anyway. If they're low-neutral, they'll most likely demand you drop the cargo. Try dropping the cargo, them immediately tractoring it back in. It gets them seriously p/o'd. Then run for it!!!
Again, best place to look for hints and tips is the spoiler forum, because any good tips and tricks are allowed there.