Something I'm surprised more people don't take advantage of is the ability to use more advanced targeting through macros than is otherwise available, especially for controller users. The best example I can think of is with macros that cast a single action, but do so on 'target of target'. I'll use as an example a WHM who's in a single-target FATE alongside non-party members, and while DPS'ing the enemy sees the main target's health rapidly declining. They know if no one bothers to heal the person, then when they either run away or die, the enemy is going to find a new target and it might be them.

A player who doesn't use macros at all has to manually retarget the person they want to heal, cast heal, and then manually retarget the enemy. 2 of those steps are unnecessary. Tabbing through a crowd to select who they already know who they want to cast on can slow them down even more, as will changing click filters to include non-party members if they use them.

But with this type of macro they can simply continue casting offensive spells against the enemy, while also casting healing spells on the player that same enemy is targeting, without changing theor target from the enemy for even a split second, by having this bound to a key/button:

/ac ”Cure" <tt>

It's as simple as that. The version I use is a more multi-purpose version of that but I should stop myself here since this isn't a macro guide thread.