“It was General Ordwin, one of the Three Heroes of the War of Liberation, who put Grust on the map. His peerless knights tamed their neighbors the barbarians in the kingdom's infancy, securing its place as one of the greatest of the Seven Kingdoms. However, the current king, Ludwik, was weak-willed and easily cowed: Doluna had little trouble forcing him into an alliance. Now he had taken ill, even as Grust suffered its string of defeats at the hand of the League. The once mighty kingdom was poised to fall...”
The following part of this article contains strategy; therefore, it is subjective, and may not work for everyone.
Having a Ballistician like Jake or Beck allows this chapter to be a bit easier. Just try to kill Camus from afar to get Gradivus from him. Or, to deal with the Ballistician without getting in someone's attack range, just place a general within their range, although you might want to keep a healer nearby. Another idea is to bring along units with a movement rate of 9 or greater, so that you may go immediately from being too far away to be hit, straight to being too close to be hit.
If you enter the village south-west of the map with Marth, you can get the staff Hammerne, which Lena can use to repair other character's weapons. You'll need this if you want to keep your Manaketes around for as long as possible in the Shin version, since unlike the original the Karyuuseki and Shinryuuseki have limited uses.
If you want to advance to the Shin-exclusive Chapter 20x: Men and Monsters, you must have 15 or less characters alive by the end of this chapter.
While you may also recruit Rolence by talking to him with Marth or Shiida in Shin Ankokuryuu to Hikari no Tsurugi, Shin Monsho no Nazo cites Marth's conversation in a flashback, seeming to imply Shiida's to be non canon... except that in the original, only Shiida can recruit Rolence, not Marth.
This is the last chapter to sell the Axe family of weapons, so if you're planning on fielding Barts, Saji, Maji, or Darros anytime in the last five chapters, now is the time to stock up on weapons for them.