With a mini voltage control circuit like the ones built in to the $35 Sensibulb LEDs.
That's why the "good" LEDs cost so much.
Or you could do the resistor in series technique which works pretty well, is a lot cheaper but you will burn out he LED sooner than the expensive ones. But how many $5 cheapo LEDs will you replace while waiting for the $35 good one to burn out? May be less expensive to go with the cheapos and swap them out when they die.
Another alternative to try, hook 2 or three of these in series. That was, at least theoretically, each light would get 1/2 or 1/3 of the voltage supply.