First and foremost, Lanterns. Elite Lanterns, or basic lanterns + the radiance augment. Your pawns don't need them, (they can help, but not much), but you do. Even in bright sunlight. The difference is huge. I used to have pics showing the difference but I just spent about 15 minutes looking for them and can't find 'em.
If you're not playing as assassin or ranger, try to stand a bit behind the pawns you want to take pictures of. Once you pause and rotate the camera (and zoom, it's not listed in the options, but it's... one of the analog sticks. Wow, why can't I remember which one...) this will get you the closest shot you can get. In this case it helps if your pawns have lanterns, as most of your light will be behind them. As Jeremiah pointed out, if you can get into tight quarters, the camera will have nowhere to go and you can also get a closeup that way. If you can find a light source like a torch or brazier near a wall, all the better.
If you're a magick archer, dodge rolling around the battlefield can get you some neat shots. If you see a pawn in combat, roll into them and pause.
Learn animations. Toss and Trigger/Advanced Trigger, as already shown above, ends with a pretty good microphone stance. Comestion ends with your pawn waving goodnight to the audience.

Running out of stamina and having two or more pawns come to aid you results in a game of rock paper scissors.

There are plenty more exploitable animations.
I admit I can't take decent shots without Lyncean Sight anymore, it's become a crutch and my Arisens have suffered for it. Lyncean Sight comes in three tiers, Keen, Lyncean and Eagle. Keen Sight doesn't zoom far at all, but it's the first one you get so it's good to practice with. The only thing you have to know is to not actually aim at what you want. Aim at the floor or the wall, or just in the opposite direction. You'll quickly notice that sometimes your pawns will disappear - either they're too close to your aiming reticle or they're too close to you, the game thinks your trying to aim at a monster so they fade out your pawn... wish I could turn off that feature. Also, sometimes your pawns will be too far away and end up looking like blocky eyeless statues. It's hard to tell the distance at which this happens, but you start to get a feel for it after a while.
Meteor Shot, the Ranger version, is almost equal to Lyncean Sight. Comet Shot goes a bit overboard with the zoom, and isn't really good for battle shots (unless you're trying for fancy saturated shots, which I'll get into later.) It IS good for closeups, though. Nothing beats it for that.

^If you aim directly opposite your pawn subject, for some reason, their eyes will be heavily outlined and any scars/makeup will be heavily darkened. Unless you like that look, try to aim down to the ground and to the left of your target. (It better avoids having your shot bisected by your arrow.)

In battle, if you can afford to, just watch the minimap. Keep moderately close to whichever pawn you want a picture of and keep using lyncean/meteor while aiiming away from them. You WILL die, unless you're out in Gransys playing with wolves and goblins.
If your pawns are rangers, try to keep on their right side. When they aim, they turn towards their right.

Fighters are hard to get shots of due to their shields. I often remove them.
Anodyne usually destroys shots. If you use a mage, don't use one that's anodyne-happy. The rippling effect makes everything blur and glow green. Again, this can be useful in saturated shots, but most of the time, it's not something you want to have to deal with.
Fulmination is the same - unless you like the effect.
Maelstrom is the bane of my existence. There is NOTHING I can do with it.
My ideal setup for a magic user is as follows:
-High Comestion. The BEST lighting you can get, right here. Awakened Daimon has a lovely double comestion, which is easily the best thing ever, even if it kills my magdef-deficient babies.

-High Brontide. It's my favorite spell. Those poses as it's being cast.

-High Miasma. Again, the pose as it's being cast. The lighting is rather nice too.

-High Lassitude. For some reason I can't find a pic of it. Trust me, it's lovely.
-High Silentium. I actually prefer this cast by the enemy, but I'll take what I can get.

-High Voidspell... just because of those leapworms. If I don't have it, the debuff turns my pawns slimy.
The mother of all spell effects, though, would have to be the Ur's holy furor. Allied holy furor/surging light tomes aren't as good, as your pawns will have a yellow/white sheen to them.

Now for some 'trick shots.' First, color saturation.

This requires Comet Shot and Tenfold Flurry, or Lyncean Sight and Fivefold Flurry.
If you've ever used the flurry skills, you'll notice the screen flashes red for a fraction of a second. The trick is to pause the game while this red is still up. It's not as hard as it sounds.
I usually have Comet/Lyncean set to X (or square) and Ten/Fivefold to B (or circle) because I find it's easiest on the fingers. Activate Comet Shot, and keep the aim button held down. Place two fingers on start and the button corresponding to the flurry skill. Press both at once. If it's successful, you'll get a mostly red-tinted screen when you turn the camera in photo mode. It also blurs things a lot, and rotating the camera sometimes just doesn't help matters. Zooming in or out (you still get a bit of leeway) usually diminishes the saturation while in photo mode.
Color saturation shines with spells. The more effects, the better. Here's a saturated brontide.

Comet Shot is better for this, as you'll lose some zoom when you shift from your zooming skill to the flurry skill.
Walking out of bounds on the surface of BBI

This requires a little trial and error. It worked flawlessly my first try, then didn't work at all on my second. First you need to grab a vase or a barrel, go to the end of the pier and jump toward the rear of the boat. You will fall and drown. Get up and dust yourself off and try again with another vase. When you begin to fall into the water, keep pressing forward and trying to jump. Eventually you will break free of the brine and can walk along the sea floor. It's quite buggy, and can take many many vases. Or two. Just make sure you're in the same spot each time, near the back of the boat at the end of the pier. In order to get back onto the pier after the world's gone crazy, walk back to it and jump up(!) into the brine. Or you can just use a ferrystone.
Group Shots

There are several places where this works, but I find the easiest is in the pig pen in the Craftsman's Quarter in Gran Soren. It takes a lot of patience and a LOT of leg work.
Pick up a roaming pawn and carry them over to the pigpen. You'll have to put them down several times to stop them from getting fed up and kicking you, depending on how far of a trek it is. Once you make it to the pigpen, there's a spot where you can clear the fence with a jump. DO NOT throw the pawn over the fence, you will get caught by Ser Raffe. (Or at least I always was.) Once placed down inside the pen, the pawn will not move. You can leave the craftsman's quarter, as long as you don't hit a loading screen, the pawn will remain there. There are about twenty roaming pawns in Gran Soren, although for some reason they seem to prioritize pawns you've hired once like 80 years ago, rather than pawns on your friends list.
Too many pawns in the pen will cause some to fade from sight, and I've heard of several crashes on the PS3 due to this, so party with caution in there.
Getting into Caxton's/Camelia's/Black cat/Duskmoon Tower doors/Everfall Doors

This is far more effort than it's worth. I just did it to see if it could be done. Never even bothered trying again.
You need a barrel. There's one in the alehouse in the corner, and one...inside the inn? I forget. Place the barrel right next to the counter of the shop you wish to enter. If your pawns don't instantly break the damn thing, stand inside the barrel and pick up something nearby - a pawn or a jar or something. (I'd say place a jar close by to start, but your pawns would probably break THAT too.) Once you're inside the barrel and carrying something, keep hopping toward the counter. It looks and feels like it won't work. Most of the time it doesn't, and you're eventually 'pushed out' of the barrel. And then your pawns DEFINITELY break it.
It does work though. If you don't think you're doing it right, you most likely ARE doing it right.
Black and White shots

This requires the Magick Archer skill Great Sacrifice, and is probably best with offline pawns, because they will be sacrificed. You'll also need either a bunch of mushrooms or a liquid vim.
-Use Great Sacrifice. Do not let go of the aim button for the remainder of this trick. Once you're able, fire off the bolt, and fire a few normal magick arrows along with it. Your stamina might be taking a huge hit, so keep an eye on it.
-Wait for the screen to turn white. When it does, use Great Sacrifice again. Wait until you see the first Great Sacrifice bolt disappear along with the first pawn you sacrificed.
-Fire off the second Great Sacrifice, and keep firing normal bolts until the screen turns white again and fades. Let go of the aim button, and the B&W should remain. If you killed your main pawn, you can get it back from a riftstone. You can't hit a loading screen, though, because that returns color to the world. You might notice color coming back when talking to people, but it returns to B&W when you come out of the dialogue box.
I'm sure there are other things I'm forgetting. If anything sounds unclear or just flat out doesn't make sense, let me know. I kept getting sidetracked.