When you unlock the door to the far right on Chapter 14, you will see a rogue named Rennac. He holds the member card for the secret shop. To get it, you must recruit him, kill him, or steal it. If you kill him, he will drop it, but you will miss a valuable character. If you steal it, he has the opportunity to kill you, so do so at your own risk. If you recruit him with Eirika, you will have to pay 10,000g. If you recruit him with L'Arachel, he will be free, which is a big advantage. He doesn't need a lockpick to open chests and doors, and is a fairly decent fighter.

To get the member card from Rennac you either steal it, kill him, or recruit him w/ Ephraim for 9980 gold or have L'Arachel talk to him without paying him. After getting the member card go to the left side of the stage where there is an archer holding an body ring(you have to steal the body ring). To the archers right will be the secret shop.

Take any of your units up to a certain character and select the trade command. Trade your weapon of choice to the top of the character's list of weapons. That weapon will now be equipped. This can come in handy when you realize you may need a different weapon then what is currently equipped.

On the right side of the stage(where there are 3 chests in a verticle line) there will be a revesed-upside down L. The secret shop will be on the right square.

To use this, go to the Tower of Valni and select four pairs of people who you want to have support each other, then start the battle, place the units that you want to have support each other in adjacent spaces and end your turn. Continue ending your turns until your units can support. After you support with all your units retreat from the Tower but DO NOT SAVE. Repeat this process until you have an A-rank suppport with your four pairs of units. Once you are done simply restart the mission you were on, but DO NOT SAVE. If done correctly your units should have no support records in thier stats, but when you go to support conversation in extras the support records will be there. Using this glitch I completed 100% support in a matter of hours.

The Triangle Attack from Fire Emblem 7 is back, but there is a catch to using it this time around. To use it, surround the desired target on three sides with Vanessa, Tana, and Syrene (whom you must safely recruit in Chapter 17), then attack the enemy. For the Triangle Attack to occur, the two supporting flyers _must_ be Falcoknights. This means that you'll have to bite the bullet and promote either Vanessa or Tana into the Falcoknight class as opposed to a Wyvern Knight.

The benefit to the Triangle Attack is that you'll get a guaranteed critical hit, and thus 3x the normal attacking damage practically whenever you want.

After you get the Secret Card, look near the boss. There are two upside down "L" shaped things. On the little part of the one on the left, there is a secret shop. Have someone with the member card in their inventory stop there to acess the shop.

When you have cleared chapter 19, go to the Ruins. When you enter retreat and save. then reset the game. If you now enter the ruins, the first wight will carry an secret book. This ONLY work when you have saved while standing on the ruins on the map and reset then.
If you enter the tower the same way (enter, retreat, save end re-enter) the bonewalker left of the boss will carry an spear.

NOTE: This doesn't work after you cleared chapter 20

In any free map that has damage tiles, kill every monster or unit except for one. Then, position a few of your units alongside the damage tiles, and remove their equipment, either by discarding it, or trading it to somebody else. If it works, the game's Enemy Ai will move the last unit on top of the damage tile. It will then proceed to attack any units it can, until it dies from the damage received by the damage tile.

Once the creature dies, the glitch activates. Even though there's no enemies left on the map, the game doesn't recognize the last monster as "dead", and the match continues until you either Suspend and Restart, or Retreat from the fight.

If this occours during the actual story mode, as opposed to a Monster Map, the current chapter will become unbeatable, requiring you to restart the chapter.

Use the Control Enemy glitch to have a monster with a flashing green "spoils" item in its inventory take the item you want restored from Supply. After making sure that your item is on the bottom of the list and is flashing green as if it were spoils, kill that monster. The monster will drop your item, however it will be totally new.
This trick can also be used on gorgon eggs, but the first item on the list will dissapear, and you must trade with them again after they hatch to regain the item. This glitch can even restore the Dragonstone.