Ten- Pin - Aim for the green pegs first and use the two boulders to finish the rest
Wreckoning - Arc the boulder so it rolls between the two blue peg arches, taking out all of the pegs in one shot.
Orange Crush - I used Gnorman for this since his lightning chains pretty well in this level.
Bowling Blind - [Video] Gnorman again; start by using the peg immediately left of the shooter to bounce straight down into a extreme slide to get the wall out of the way and to get a couple of extra balls. Once you have Gnorman's power up, aim for the orange clusters.
Trollin' With Style - The easiest skill shots to get, especially on this trial, are the free ball skill shots, which require you to bounce the ball off a peg and into the bucket at the bottom of the screen. To do this, clear out the column of pegs directly below the ball shooter, and then starting banking balls of the either side of the walls that go down the middle of the screen as the bucket passes underneath to bounce the ball from the rectangular peg and into the bucket 5 times.
10% of a Billion - [Video] Use the first two shots to hit as many orange pegs as possible to build up a combo, then start focusing on mixes of purple and orange, then when there's only one or two orange pegs left, take out any remaining clusters of purple pegs before finishing off the last orange peg. You will want a ton of extra balls, and to land in the 100,000 point bonus bucket at the end to ensure you get well over 1,000,000 points.
Open Orange - The general trick for this is to use your first two balls to slide down the ramps in the middle of the level, and then clear out the sides. I would recommend using Gnorman, as he can wreak havoc with a good bounce.
At Least it's an Ethos - Another trial where you need to stay below a certain score (175k), which is funny, since I consistently do better on these without trying, than I do on other levels. Although it doesn't make too much of a difference, I would recommend going with Bjorn as his ability is probably the least capable of score boosting, and also allows you to shoot around purple pegs.
The Circular Condition - Aim for the left side of the outer ring to use the momentum of the rings to move the boulder toward the middle of the rings as it goes down the screen. Repeat the process three times and you should be done.
The Gorge - As the tip suggested, I used Jeffrey to boulder through this level since his boulders are able to go straight down through the stronger blocks, while the Gnorman alternative has to go around them. With an ideal peg color setup, you will start off by shooting a green peg near the middle of the level, and use that boulder to clear out a cluster of green pegs on either end of the screen. Then clear out the other side, and any leftovers.