Here's a composite image of my fifth Goblin Camp camp:
Population around one hundred; click on the picture for a closer look. You can see some of the main features of the camp pretty well in this large-scale image. Your orcs and goblins muddy up the ground and leave copious amounts of filth behind; you can see the main thoroughfares outlined in brown, as well as the brown piles of filth at the south and west gates, because of the permanent guard stationed there. And then there is, of course, the giant pile of filth that is the main camp, slowly spreading outward and seeping into the river.
For security, I've gone with a concentric layout of palisades and moats. There are gates and bridges only at certain points, which channels incoming attackers there, to be dealt with by my guards. The other security risks are the improvements that occasionally spawn monsters; ants will attack from your stone quarry, golems from the clay pit and so on. You can see all of these improvements just south of the south gate, meaning that mostly (mostly) the guards at my south gate deal with the bad guys before they get into my camp.
Another notable feature are the huge lumber yards that dominate the outer two circuits of the camp. The game is set in a forest, and one ends up cutting down quite a few trees to make way for moats, workshops, stockpiles and so on. Of course, you could just leave the logs lying around, but I like my huge lumberyards.
Now that I have a camp this size, I thought I might weigh in on some problems I've read about people having with Goblin Camp. For starters, several people have complained that their camps get bogged down with interminable hauling jobs, especially of seeds. If you take a look at my camp here, you may notice that the fields aren't very large at all. That's because in my experience, it's very easy to destroy the efficiency of your camp through one simple expedient: overfarming.
Starvation is a constant threat early in the game, so I see the appeal of planting as many crops as possible. The problem is that the yields in the game are quite generous: bloodberries IIRC 5:1 and nightbloom trees 4:1, and with very little wastage. In 0.13, you start with 30 bloodberry seeds. Plant all of them, and by next fall you have 150. Another year of maximum bloodberry farming? 750. And so on. See where the endless seed hauling jobs come from? The size of the fields needs to grow relative to the size of the population in the camp. It's not that hard; as you might guess from the name, this is my fifth camp, and because I got the farming right from the get-go, I never had a problem with starvation.
The other point is that the day-to-day operation of a goblin camp is messy in many ways. Seeds and other things just end up lying around and if you're anal-retentive, they need to be cleaned up into their appropriate stockpiles. Another essential thing is to give your goblins time to do that. If they're constantly running around on errands and constructions jobs, the hauling jobs are going to spiral out of control because nobody's doing them. So take a break every now and then and let your goblins clean up the camp. Even with that camp, I've managed to get my jobs list down to one screen.
Managing your job queue is a question of resource management, and that is, after all, the point of the game.