If your in england, the southern hemisphere, try to find a northfacing slope. This is where the sun will be all day, and you'll get the best results. My current 2010 outdoor grow (im in the northenr hemisphere) consists of:
About 15 plants. I was planning on 20 but I don't have enough space.
I found a really dense thicket, and cut a path in it at rabbit height.
The soil is super rich, and already is full with rabbit droppings (which are a good fertilizer)
the thicket is in the plant of scotch broom, which is ALREADY a nitrogen fixer!!
I have two plots in this thicket, which is a south facing slope
I have yet to dig my 4x4x5 reservoir, hooked up to a gravity speed drip system (the reservoir is above the plants.
I dug holes about 3x2 in size, and will mix the soil amendment and compost in with the original soil, then re fill the holes.
when the plants are young, I'll have cages over them to discourage rabbits and other varmints. I'm starting the seeds inside for 3 weeks to a moth, then harden them off, then transport to the grow area.
For the late harvest season, when it starts raining, I will hook up 4 posts at the perimeter of each of my plots, and keep a large rolled up sheet of painters plastic attached to 2 of the poles. when it rains, I just unfold the painter plastic and taught it over the other two poles (Ariel patrols are non existent in my area, they'd just think it was a hobo camp.) this is to stop bud mold.
The first thing you have to do before you grow in the woods is to NOT be attached to your plants. High likely hood of thieves, feds, animals, pests, etc. You just gotta roll with the punches, and adapt to any situation. Learn to understand what the sings of nature are telling you. Understand bird alarms, animal signs (like hair), tracking, human presence etc. follow your innervision. If you get uncomfortable while in your grow area, SCRAM. I know its sort of selfish, but you'll have to let your ladies take the flak, and save yourself. You can always grow more, don't risk being caught or hurt trying to protect your girls.
In all likely hood, when something goes right, you'll plant 20 seeds, a few will be male, and a few will be shitty or unhealthy. A good harvest from 20 seeds is 7-10 strong plants. If you plant early, or start them inside, you can clone the healthy ones to get more plants, if you wish.
thats my .2 cents.