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A consolidated list of several useful FFXIV "Life-Hacks" that you might not know about to make your life easier. Comment below if you have any more good ones!
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If you hit your Dismount button while jumping at the same time (mid-air), there is no Dismount delay

/blist add <r> automatically prompts you to Blacklist the last person that /tell you

Putting /macroicon "Spell Name" on the first line of your Macro shows the CD on the button still

If you right-click the quest/FATE turn-in icon, you can automatically select the item

Clicking the Gil icon switches between your current Gil and Company Seals

The 2 arrows beside the "Leave" Button in your Social Pane (O) allow you to re-arrange your Party order

Selling stacks to a vendor from your 3rd and 4th bag slot don't prompt you to enter an amount to sell (sells the whole stack automatically)

Always +1 Relic Glow macro: [first line] /bm [second line] /sit (It will glow until you sheathe it or enter combat again, visible to everyone)

In the HUD Layout, Ctrl + Home changes the size of the currently selected UI element (3 different sizes), this also works on most Panes outside of the HUD Layout

Set a macro to [first line] /hotbar display 8 on, [second line] /wait #, [third line] /hotbar display 8 off, to enable a popup hotbar for a set amount of seconds so you can click rarely used abilities (Bard Songs, LB, Food, Long Cd's)

Check "Play sounds when window is not active" in the System > Sound settings to hear your DF/Tells while you are Alt Tabbed

Putting the word "motion" after any default emote makes the action without showing the chat emote. ex) /panic motion

/pcmd add "Player Name" allows you to add Party members without searching for them/being near them

Enabling "Legacy Type" movement in Settings will prevent your character from backpedaling (character runs towards camera instead)

Linkshells are sorted by default based on how long people have been in the LS (longest at top)

You can have up to 2 Retainers, which not only sell your items on the Market Board, but are used as "Banks", with 7 pages each.

Setting a hotkey to "Target Closest Enemy", then using Tab Target after, is substantially more accurate than just using Tab Target

When porting from a city, step outside one zone closer to reduce the Teleporting Cost

0 on the Numpad acts as a "Confirm Button" to help skip Cutscenes/Selections faster

If you have a low level class (to save repair fees), switch and kill yourself for a Free Return to Homepoint

When doing Lower Level Story Quests, Set "Horizon" as your Homepoint, you have to return there quite often

If Crafting or Farming a specific item, drop one of them from your inventory onto your Hotbar to see how many you have left or have obtained

Typing <pos> in any chat window will Show your current coordinate position and zone (Useful for asking for a Raise)

Alt + H = Shout. Alt + L = Linkshell. Alt + S = Say. Alt + P = Party. Alt + F = Free Company(?)

Clicking the Time changes the clock from Local Time, Server Time and Game Time

You can change your chat default by typing /shout [enter], /p [enter], /s [enter] etc… this also works for Linkshells by using /l, /l2, /l3 and so on for each Linkshell

/? <command> shows you a list of parameters about the command (ex. /? search, /? hud)

Below the "Close" button when selling items on a Retainer, there is a Market History
Button that shows you recent sales/prices

You can use Shift + # to cycle your Main Hotbar between other hotbars (or Shift + Arrow Up/Down I believe)

/c "Player Name (don't close quote) allows you to Examine a player without clicking on them, if they are in Range and Line of Sight

You can type or Macro /hud "Element Name" to Toggle Hud Elements On/Off

Cheers, hopefully you learned something you didn't already know!
Thanks so much for the crazy Upvotes and the replies with some other tips! I've added some of them, and will continue to do so as comments come in. Try to keep them to ones that are sort of "Secret" or "Life-Hacks" that most people might not know, instead of obvious Hotkeys and the like.

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