Fire Emblem: Radiant Dawn/Part I/Chapter 4

This is the first of many chapters that you can access from the base. If you view the info conversations, you can recruit Meg, a level 3 armor sword. She's pretty weak and not recommended, so bench her. Regardless of what the twins say about forging, you don't have to sell weapons to forge new ones – unless you're playing the Japanese version.

Use Aran, who you (hopefully) recruited in the chapter before. He has great defense and will have no trouble dealing with the enemies in the next chapter. Forge whatever weapons you need. If you are using Edward, forge a high might and critical sword. Forge a lance with slightly higher accuracy and high critical for Aran. Also get a bronze knife for Sothe, as it can attack indirectly.

Once you're ready, start the battle!