Alternate opening sounds
In order for this trick to work, you must be running the Playonline viewer in windowed mode. Open the viewer, and as soon as the window shows up, click outside of the window, which will un-highlight the viewer. Instead of the standard music, you should hear cheering, followed by "Welcome to Playonline".

Final Fantasy logo
When you board the airship and the screen is on Steiner in the front of the ship, in the background clouds you can see the Final Fantasy symbol fly by every few seconds

Grass Cloth
Synthesis Yagudo Necklace with a Wind Crystal. This will get you three spools of Grass Thread. Synthesis them with Earth Crystal to get Grass Cloth

Orc jumps tree while attacking
Go into West Ronfaure and find an Orc (any kind) near a tree. Attack the Orc and get on one side of the tree. Make sure that the Orc is on the exact opposite side. When in the correct location, the Orc will attempt to attack you, fly up into the tree, and fall back down in front of you. Note: The Orc still causes damage to you while in the tree

Raise White Magic level easily
This trick is useful to level up much needed spells such as Protect, Cure, and Shell. Go to a local residential area and stand directly outside your Mog House. Cast the desired spell on yourself until you run out of MP. You can also cast it on other players running in and out of their Mog House. Once you have run out of MP, run into your Mog House, replenish it, exit, and repeat. This saves a large amount of time from having to heal after casting. You can level up magic by casting the spell on yourself, despite if you already have the enhancement on yourself or have 100% HP. Keep casting and it will level up

San d'Oria: Recommended places to level up
Go to the following locations in San d'Oria when at the indicated levels to level up easily.

Level 1 to 7: West and East Ronfaure
Level 7 to 13: Ghelsaba Outpost
Level 14 to 18: Valkrum Dunes
Level 19 to 25: Peninsula
Level 26 to 34: Jugner Forest
Level 35 to 43: Davoi (possibly)
Level 44 to 52: Xarbard
Level 53 to 60: Deep King Ramperre's Tomb
Level 61 to 75: Ifrit's Caltron