Anime speculation time!
Here's my guess for how the anime adaptation is going to go for the first 12 episodes:
Ep3 = Ch15-16 (Eren's training until they discover the defective equipment and he realizes he doesn't suck)
Ep4 = Ch17-18 (More training in the open areas, learning to move as a group and fight against cardboard targets, etc. Plus Rivail cameo.)
Ep5 = Ch3-4 (This is probably going to be the first big action episode, ending with Eren getting eaten. Non-readers are going to go nuts. Lol)
Ep6 = Ch5-6 (Mikasa episode, including her flashback with Eren.)
Ep7 = Ch7-8 (This one will probably end with the Eren-Titan fight mid-ch8.)
Ep8 = Ch8-9 (This will be the rest of the rescue operation using Eren-Titan ending with him transforming back.)
Ep9 = Ch10-11 + 9.5? (I can see them using the Rivail chapter as a pre-OP sequence for an episode around this point. The rest of the episode will be about them "testing" Eren after surrounding him.)
Ep10 = Ch11-12 (They'll probably have more expanded material here to show the aftermath of the discovery of a human-Titan. Plus the planning for the operation to close the wall with the rock, etc.)
Ep11 = Ch12-13 (The operation itself until Eren collapses and they all lose hope as he just stays immobile. Cliffhanger.)
Ep12 = Ch13-14 (Getting Eren back up all the way until he plugs the hole with the rock.)
Ep13 = Ch18 (I'm less sure about this, but it would make sense to have an epilogue sort of episode like ep2, where they remember and honor the fallen, and have expanded scenes on the cleaning up of the city and so on, with the characters reflecting on their first major battle.)
This will mean they'll cover about 18 chapters with 12-13 episodes. The second half of the series will start with Eren in the cell, and the new OP sequence will probably feature tons of Titan on Titan action.
What do you guys think?