I'm no expert so take this with a grain of salt...
I would also recommend research and reading everything you can find. It ain't hard to grow a weed but getting something worthy of smoking is a different thing entirely.
But for what it is worth -- here is a synopsis of what i've learned from this site, other reading and very limited experience.....you'll need:
1) Space - you already have that but it should be enclosed so you can have more control over ventilation, heat, humidty, security, etc..
2) Lights - very important. You need something that replicates sunlight as closely as possible. I'd recommend HID or High Intensity Discharge lighting (MH or Metal Halide for grow and HPS or High Pressure Sodium for flowering) but this site has a lot of proponents of CFL and other types of light. So your mileage may vary.
3) Something to put the plants in - soil or hydro? This can be a huge discussion so you have to decide if you're going with soil or hydro then go from there. The answer to this question can help determine how often to water (with hydro you are on a schedule - w/soil you check the soil and water accordingly). Soil vs. hydro can also define what nutrients you use and a few other choices you'll need to make.
4) Ventilation/Air Circulation - you'll need at least an 1) exhaust fan (to remove heat and replace CO2), an 2) air intake hole or fan (a passive air intake hole should be slighly larger than the exhaust opening to improve fan life and to avoid creating a vacuum in an airtight chamber) and a 3) circulating fan blowing on the plants (to strengthen them and keep air moving)
5) Odor control? this would include carbon filters/ozone generators
You'll also need nutrients and seeds. My opinion (and some others have recommended this also) is to start with bag seeds until you have had some success and then buy some decent seeds. As for nutrients or nutes, you can look online and find a ton of info but they usually break down into grow and bloom formula with a possible third one. For example: General Hydroponics has Flora Micro, Flora Grow, and Flora Bloom. You use all three for all growth/bloom phases but in different amounts (more grow during vegetative, more bloom during flowering). Instructions are on the packages. I think one of the easiest (and highly concentrated) choice would also be from General Hydroponics and that is the Flora Nova series. There are only two (grow and bloom). There are also a lot of supplements, foliar feeding, and other nutrients but using grow/bloom works fine. One word of caution - a little bit of nutes goes a long way!
Another thing you should know is how the plant grows. It obviously starts as a seed or cutting (clone), then enters the seedling stage. Vegetative is the next stage with flowering being the final stage before either dropping pollen (male) or generating seeds (female). Keep all the males out of your grow room and the females will not be pollinated. But instead will grow big resinous seedless buds (sinsemilla)! This is the point of getting rid of the male plants.
So it goes:
1) Cloning or seed germination
2) Seedling
3) Vegetative
4) Flowering
After the plant is done flowering and ready to harvest (a large percentage of the stigmas turn amber or brown), you cut it down, trim it, hang it in the dark (or in a paper bag) until the stems snap when broken and then you can start slowly curing it. You put the dry bud in jars or tupperware and release air daily (if mold forms get rid of the moldy bits and go back to the drying stage). Don't rush this step! the slower the dry/cure - the more tasty the smoke! Eventually the bud will not remoisten and at that point it is completely ready for storage and enjoying!
This was obviously a very brief overview with many missing bits of information. Please let me know if anything should be changed or corrected otherwise - good luck, have fun and happy growing!
