Easy money:
Find any mission that has an advance payment. Start the mission and immediately abort it. After this is done, you will see your earnings displayed in two boxes. One box is for your new money amount that was earned and one for the deductions for repairs, ammunition, and the special deduction in the event that something was destroyed that was not supposed to. Note that there is no deduction, and you will get the amount that was promised to you in advance. Make sure to save your game before you do this, as the game will end if this is done too many times.
Takeover New Fortress mission: Hidden part:
When you battle against the two ACs fly up into the giant hole in the ceiling. When you look up, there should be a pipe that runs from one side to the other. On top of the pipe is the FCS part PLS-SRA02.
Add defeated AC emblems:
Press Select + Start when the victory message appears in the arena to add the defeated AC's emblem to your list.
Prototype parts:
If you use a certain type of leg part (light weight leg, middle weight leg, hover, etc.) for enough missions, a "prototype" part will be unlocked in the shop. The prototypes are usually good. This may also be the case with other parts as well.
Bonus parts:
For every mission you get an "A" or "S" rank on, you will get a special bonus part.
Easy Arena wins:
Select the Trene City area. When the battle begins, there is a big building directly in the middle of the Arena floor. Boost up to the top of the building and pummel the opponent AC full of rockets or other types of ammunition that can lock on. If you are unable to boost up the entire way, there is a ledge halfway up. Rest there momentarily, then boost the rest of the way. Weapons that are the most effective are the small rockets and/or vertical missiles. There are some enemies that are too fast to do this to; they move to much to get a lock on. If this happens, when you start, boost West and position yourself in between two buildings very close to the border. Most of the enemy ACs will not go behind because they will lose. They will just move back and forth trying to get a fix, but will not approach you if you are very close to the border. Pop in and out from behind the building and shoot various rockets and missiles as the ACs are moving around. It is slightly time consuming, but a very easy way to boost ranks early.
Explore Unexplored Region mission: Hidden part:
Go into the crater to find a plane. Shoot the back end of the plane to destroy that section. Inside the plane is the back part MWC-OC/30.
Infiltrate New Base mission: Hidden part:
In a cave in the middle of the map is the extension part MWEM-R/36.
Investigate mission:
Go to the first door, unlock the control panel, then search for the second one. In the room where there is a ventilation duct, shoot the duct. Fly up, then go down into the other room it leads to. Destroy all the boxes to find the left arm part KWG-NHZL60.
Search Vilius Laboratory mission: Hidden part:
Search the bottom of the deepest pit to find a part guarded by a MT. It is the left arm part MWG-KPL/150.
Protect Part Transport mission: Hidden parts:
Wait until the plane lands, then get behind the it. Shoot the back end until the door explodes. Press Circle next to the part to get the right arm part CWG-ARF-180.