Having well written macros can make or break your performance within FFXI. I won't get into in depth macro writing, but here's a few pointers that will help you out in the heat of the moment.
Are you tired of that one person dying because every time you go to heal him, he changes gear and you lose your target? This can be fixed in two easy ways.
<stal> or <stpt>
As I'm sure you've already figured out, al is for Alliances, pt is for parties. Examples:
/ma "Cure VI" <stal>
/ma "Regen IV" <stpt>
Will give you a cursor on the party lists that you can scroll up or down till you find the target you need. Even if they change gear, you won't lose focus as you're targetting the list, and not the player. While both commands will target the party list and not the individual player, stpt will only target your party, so it's recommended you only use that for spells that can only target your party, such as Regen.
Are you attacking one mob, and want to use an ability or spell on another?
<stnpc>
This will allow you to scroll around until you find the mob you want. Warning, this will target any object that can be targeted that is not player controlled. This includes ??? marks, NPCs, or treasure chests.
/ja Provoke <stnpc>
This will allow you to be attacking one mob, and choose a different target to provoke. Also useful for Black Mages who want to focus on killing one mob, but need to quickly stun, sleep, bind, etc another mob.
Do you want to easily trade items to an NPC, Treasure Chest, ???, but are getting tired of opening your menu, selecting trade, finding the item, then clicking OK to trade?
/item "Item Name" <t> or <stnpc>
Either way will work. If you use <t>, you have to have your intended target targeted already. <stnpc> will allow you to find your target before trading. For example:
/item "Imp. Brz. Piece" <t>
Do that half a million times and your Mog House won't expire till 2014 like mine!
If you want a visual cue as to if your macro is going off, use the /echo command. This will put text into your text box only showing that your macro went off.
/echo Cure VI
If this is at the end of your Cure VI macro, it will be displayed in your text box only, showing that you hit your Cure VI macro. /echo works just like /party, /linkshell, /say, /shout, except that only you see /echo
Do you want to know how much time is remaining on a spell?
/recast "Spell or Job ability"
This will echo to your text box how much time is remaining on the recast of a spell or Job Ability.
For all macros, if you're calling an ability, spell, item, or piece of gear, you MUST use "" around the name if it is more than one word. If it is only one word (such as Provoke, Warcry, Phalanx) you can still use "", but they are not required.
Be smart with your macros. And for the love of god, we do not need to know if you're summoning an avatar, calling your wyvern, calling a jug pet, calling your automaton, casting spells on anyone, or any other action that you may do often! You may think you look witty with your sic macro, but after the second mob we fight, it gets old, fast. Yes, it's nice to know that you're casting Cure IV on me to save me, but you don't need to let the entire party know, just do it and I'll be happy.
The only time you should ever have /p macros are for actions that may cause worry, such as convert or spirit link where your HP will drop drastically with no apparent reason, or if you're using an ability that might cause others to not use items, such as Devotion. You may think you're being clever with adding "/p Rainbow Brite, see the shining light!" to your Chi Blast macro, but everyone else thinks you're an idiot.