/macroicon "Sleep"
/ac "Sleep" <t>
/p Casting Sleep on <t>

This will put the sleep cooldown on the macro (you will still need to find the icon in the image list, this is just the timer), and sleep whatever you have targeted as well as let the party know you are sleeping so a BLM or other WHM doesn't waste their sleep. Another good one for WHM would be:

/macroicon "Swiftcast"
/p Rasing <t>
/ac "Swiftcast" <me>
/ac "Raise" <t>

Usually you would still use the Raise Icon, but this puts a timer for when Swiftcast is available and allow you to do a fast raise with one button. Then if swiftcast is not available you just keep mashing the button to skip the swiftcast line and cast a slow raise (or you can have the normal raise on your bar too). The /p line notifies your party so the other healer doesn't waste a swift raise too/ the person knows not to return. Sometimes you will see people put a jab/joke in the /p like "TIME TO WAKE UP, RAISING <t>" or "STUPID DD, learn to dodge" etc.