You don't get rid of weed odor, you learn to control it. Seal your grow room as good as possible is the step that I find most people skip. Next you need to have a good air exchange system, pumping stink and heat out, and bringing cool fresh CO2 rich air in. Be sure to have the exhaust tube where it won't be smelt or noticed, out the roof, tapped into the chimney, out a back wall into a hard to get to area, you get the idea.
Carbon filters are a good addition also, mount a can filter and run a circulation fan sucking air thru the filter, this helps cut down the smell, and you can use this fan as your dedicated fan needed to blow on your plants at all times to help cool them and strengthen the stalks.
Hope this helps, good luck and happy grows!