When deciding to grow marijuana some people suggest it's best to consult the internet. Personally I am very fond of the book - deluxe edition 'Marijuana Growers Guide". It covers everything in good detail and costs under $20.00.
The method I describe here is simple and effective, and provides a large yield all at once. If you want continuous production methods buy the book mentioned above. Apart from that, and without financial considerations, I will try to list what I consider some great ideas for growing marijuana.
To get started you are going to need some lighting. Either Metal Halide (MH) or High Pressure Sodium (HPS) lighting will work for all stages of the grow cycle. MH is better for vegetative growth and HPS for the flowering stage, but let's put that aside. Buy a 600 watt MH or HPS. Always keep you light 6 inches to 12 inches above the top of you plants.
Next make 4 rectangular containers, each a little less than 2.5 feet wide and 4 feet long, and 18" deep. Put them on wheels and give them drainage holes. You will get a much higher yield in the same space if you grow 20 to 40 plants in 4 containers rather than in individual containers. In rectangular rooms use rectangular containers so as to maximise your space.
Make sure the walls and if possible floor are highly reflective. I recommend white paint instead of mylar because it is cheaper, easier and almost as reflective. Before you put any of the containers or soil in, clean the walls, floor and ceiling with a bleach and water solution to disinfect any mold or other potentially hazardous pests.
Next, fill the bottom of your containers with rocks or clay pellets and make sure they are clean to allow drainage. Then fill your containers all the way to the top with potting soil (mix in some 'diatomaceous earth' for preventative pest control and trace minerals).
I like to add a thin layer of perlite to the top of the soil after my plants are in because it is reflective (although can be dusty). Buy a light timer, a thermometer and a fan and you are ready to grow. You don't need to mess with fertiliser (stay organic if possible) except something with high phosphorous (like 10-60-10) for when you are budding.
Go easy on the water and fertiliser your first time out, better to be a little light than a little heavy (organic also reduces the risk of fertiliser burn). You should certainly be able to pick up the rest from there.
That's pretty much all you need to know to get started growing marijuana plants. Make sure you choose good cannabis genetics when buying your cannabis seeds too, it will make a big difference to the quality of the end product.